description: You are given a string s, consisting of n letters, each letter is either 'a' or 'b'. The letters in the string are numbered from 1 to n.
  
  s[l; r] is a continuous substring of letters from index l to r of the string inclusive. 
  
  A string is called balanced if the number of letters 'a' in it is equal to the number of letters 'b'. For example, strings "baba" and "aabbab" are balanced and strings "aaab" and "b" are not.
  
  Find any non-empty balanced substring s[l; r] of string s. Print its l and r (1 ≤ l ≤ r ≤ n). If there is no such substring, then print -1 -1.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of testcases.
  
  Then the descriptions of t testcases follow.
  
  The first line of the testcase contains a single integer n (1 ≤ n ≤ 50) — the length of the string.
  
  The second line of the testcase contains a string s, consisting of n letters, each letter is either 'a' or 'b'.
  
  Output
  
  For each testcase print two integers. If there exists a non-empty balanced substring s[l; r], then print l r (1 ≤ l ≤ r ≤ n). Otherwise, print -1 -1.
  
  Example
  
  Input
  
  
  4
  1
  a
  6
  abbaba
  6
  abbaba
  9
  babbabbaa
  
  
  Output
  
  
  -1 -1
  1 6
  3 6
  2 5
  
  Note
  
  In the first testcase there are no non-empty balanced subtrings.
  
  In the second and third testcases there are multiple balanced substrings, including the entire string "abbaba" and substring "baba".
solution: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.util.Arrays;
  import java.io.UncheckedIOException;
  import java.io.Closeable;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.util.InputMismatchException;
  
  /*
  @author : sanskarXrawat
  @date   : 9/9/2021
  @time   : 1:35 PM
   */
  @SuppressWarnings("ALL")
  public class BalancedSubstring {
  
  
      public static void main(String[] args) throws Throwable {
          Thread thread = new Thread (null, new TaskAdapter (), "", 1 << 29);
          thread.start ();
          thread.join ();
      }
  
      static class TaskAdapter implements Runnable {
          @Override
          public void run() {
              InputStream inputStream = System.in;
              OutputStream outputStream = System.out;
              FastInput in = new FastInput (inputStream);
              FastOutput out = new FastOutput (outputStream);
              Solution solver = new Solution ();
              solver.solve (1, in, out);
              in.close ();
              out.close ();
          }
      }
  
      @SuppressWarnings("unused")
      static class Solution {
          static final Debug debug = new Debug (true);
  
          public void solve(int testNumber, FastInput in, FastOutput out) {
  
              int test=in.ri ();
  
              while(test-->0){
                  int n=in.ri ();
                  char[] s=in.readString ().toCharArray ();
  
                  int l=-1,r=-1;
  
                  for (int i = 0; i <n-1; i++) {
                      if(s[i]!=s[i+1]){
                          l=i+1;
                          r=i+2;
                      }
                  }
                  out.prtl (l+" "+r);
              }
  
          }
  
      }
  
  
      static class FastOutput implements AutoCloseable, Closeable, Appendable {
          private final StringBuilder cache = new StringBuilder (THRESHOLD * 2);
          private static final int THRESHOLD = 32 << 10;
          private final Writer os;
  
          public FastOutput append(CharSequence csq) {
              cache.append (csq);
              return this;
          }
  
          public FastOutput append(CharSequence csq, int start, int end) {
              cache.append (csq, start, end);
              return this;
          }
  
          private void afterWrite() {
              if (cache.length () < THRESHOLD) {
                  return;
              }
              flush ();
          }
  
          public FastOutput(Writer os) {
              this.os = os;
          }
  
          public FastOutput(OutputStream os) {
              this (new OutputStreamWriter (os));
          }
  
          public FastOutput append(char c) {
              cache.append (c);
              afterWrite ();
              return this;
          }
  
          public FastOutput append(String c) {
              cache.append (c);
              afterWrite ();
              return this;
          }
  
          public FastOutput println(String c) {
              return append (c).println ();
          }
  
          public FastOutput println() {
              return append ('\n');
          }
  
          final <T> void prt(T a) {
              append (a + " ");
          }
  
          final <T> void prtl(T a) {
              append (a + "\n");
          }
  
          public FastOutput flush() {
              try {
                  os.append (cache);
                  os.flush ();
                  cache.setLength (0);
              } catch (IOException e) {
                  throw new UncheckedIOException (e);
              }
              return this;
          }
  
          public void close() {
              flush ();
              try {
                  os.close ();
              } catch (IOException e) {
                  throw new UncheckedIOException (e);
              }
          }
  
          public String toString() {
              return cache.toString ();
          }
  
          public FastOutput printf(String format, Object... args) {
              return append (String.format (format, args));
          }
  
          private static int countDigits(long l) {
              if (l >= 1000000000000000000L) return 19;
              if (l >= 100000000000000000L) return 18;
              if (l >= 10000000000000000L) return 17;
              if (l >= 1000000000000000L) return 16;
              if (l >= 100000000000000L) return 15;
              if (l >= 10000000000000L) return 14;
              if (l >= 1000000000000L) return 13;
              if (l >= 100000000000L) return 12;
              if (l >= 10000000000L) return 11;
              if (l >= 1000000000L) return 10;
              if (l >= 100000000L) return 9;
              if (l >= 10000000L) return 8;
              if (l >= 1000000L) return 7;
              if (l >= 100000L) return 6;
              if (l >= 10000L) return 5;
              if (l >= 1000L) return 4;
              if (l >= 100L) return 3;
              if (l >= 10L) return 2;
              return 1;
          }
  
          private static int countDigits(int l) {
              if (l >= 1000000000) return 10;
              if (l >= 100000000) return 9;
              if (l >= 10000000) return 8;
              if (l >= 1000000) return 7;
              if (l >= 100000) return 6;
              if (l >= 10000) return 5;
              if (l >= 1000) return 4;
              if (l >= 100) return 3;
              if (l >= 10) return 2;
              return 1;
          }
  
      }
  
  
      static class FastInput {
          private final StringBuilder defaultStringBuf = new StringBuilder (1 << 13);
          private final ByteBuffer tokenBuf = new ByteBuffer ();
          private final byte[] buf = new byte[1 << 13];
          private SpaceCharFilter filter;
          private final InputStream is;
          private int bufOffset;
          private int bufLen;
          private int next;
          private int ptr;
  
          public FastInput(InputStream is) {
              this.is = is;
          }
  
          private int read() {
              while (bufLen == bufOffset) {
                  bufOffset = 0;
                  try {
                      bufLen = is.read (buf);
                  } catch (IOException e) {
                      bufLen = -1;
                  }
                  if (bufLen == -1) {
                      return -1;
                  }
              }
              return buf[bufOffset++];
          }
  
          public void skipBlank() {
              while (next >= 0 && next <= 32) {
                  next = read ();
              }
          }
  
          public String next() {
              return readString ();
          }
  
          public int ri() {
              return readInt ();
          }
  
          public int readInt() {
              boolean rev = false;
  
              skipBlank ();
              if (next == '+' || next == '-') {
                  rev = next == '-';
                  next = read ();
              }
  
              int val = 0;
              while (next >= '0' && next <= '9') {
                  val = val * 10 - next + '0';
                  next = read ();
              }
  
              return rev ? val : -val;
          }
  
          public long readLong() {
              boolean rev = false;
  
              skipBlank ();
              if (next == '+' || next == '-') {
                  rev = next == '-';
                  next = read ();
              }
  
              long val = 0L;
              while (next >= '0' && next <= '9') {
                  val = val * 10 - next + '0';
                  next = read ();
              }
  
              return rev ? val : -val;
          }
  
          public long rl() {
              return readLong ();
          }
  
          public String readString(StringBuilder builder) {
              skipBlank ();
  
              while (next > 32) {
                  builder.append ((char) next);
                  next = read ();
              }
  
              return builder.toString ();
          }
  
          public String readString() {
              defaultStringBuf.setLength (0);
              return readString (defaultStringBuf);
          }
  
          public int rs(char[] data, int offset) {
              return readString (data, offset);
          }
  
          public char[] rsc() {
              return readString ().toCharArray ();
          }
  
          public int rs(char[] data) {
              return rs (data, 0);
          }
  
          public int readString(char[] data, int offset) {
              skipBlank ();
  
              int originalOffset = offset;
              while (next > 32) {
                  data[offset++] = (char) next;
                  next = read ();
              }
  
              return offset - originalOffset;
          }
  
          public char rc() {
              return readChar ();
          }
  
          public char readChar() {
              skipBlank ();
              char c = (char) next;
              next = read ();
              return c;
          }
  
          public double rd() {
              return nextDouble ();
          }
  
          public double nextDouble() {
              int c = read ();
              while (isSpaceChar (c))
                  c = read ();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read ();
              }
              double res = 0;
              while (!isSpaceChar (c) && c != '.') {
                  if (c == 'e' || c == 'E')
                      return res * Math.pow (10, readInt ());
                  if (c < '0' || c > '9')
                      throw new InputMismatchException ();
                  res *= 10;
                  res += c - '0';
                  c = read ();
              }
              if (c == '.') {
                  c = read ();
                  double m = 1;
                  while (!isSpaceChar (c)) {
                      if (c == 'e' || c == 'E')
                          return res * Math.pow (10, readInt ());
                      if (c < '0' || c > '9')
                          throw new InputMismatchException ();
                      m /= 10;
                      res += (c - '0') * m;
                      c = read ();
                  }
              }
              return res * sgn;
          }
  
          public boolean isSpaceChar(int c) {
              if (filter != null)
                  return filter.isSpaceChar (c);
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          public interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
          }
  
          public final int readByteUnsafe() {
              if (ptr < bufLen) return buf[ptr++];
              ptr = 0;
              try {
                  bufLen = is.read (buf);
                  if (bufLen > 0) {
                      return buf[ptr++];
                  } else {
                      return -1;
                  }
              } catch (IOException e) {
                  throw new UncheckedIOException (e);
              }
          }
  
          public final int readByte() {
              if (ptr < bufLen) return buf[ptr++];
              ptr = 0;
              try {
                  bufLen = is.read (buf);
                  if (bufLen > 0) {
                      return buf[ptr++];
                  } else {
                      throw new java.io.EOFException ();
                  }
              } catch (IOException e) {
                  throw new UncheckedIOException (e);
              }
          }
  
          public final String nextLine() {
              tokenBuf.clear ();
              for (int b = readByte (); b != '\n'; b = readByteUnsafe ()) {
                  if (b == -1) break;
                  tokenBuf.append (b);
              }
              return new String (tokenBuf.getRawBuf (), 0, tokenBuf.size ());
          }
  
          public final String nl() {
              return nextLine ();
          }
  
          public final boolean hasNext() {
              for (int b = readByteUnsafe (); b <= 32 || b >= 127; b = readByteUnsafe ()) {
                  if (b == -1) return false;
              }
              --ptr;
              return true;
          }
  
          public void readArray(Object T) {
              if (T instanceof int[]) {
                  int[] arr = (int[]) T;
                  for (int i = 0; i < arr.length; i++) {
                      arr[i] = ri ();
                  }
              }
              if (T instanceof long[]) {
                  long[] arr = (long[]) T;
                  for (int i = 0; i < arr.length; i++) {
                      arr[i] = rl ();
                  }
              }
              if (T instanceof double[]) {
                  double[] arr = (double[]) T;
                  for (int i = 0; i < arr.length; i++) {
                      arr[i] = rd ();
                  }
              }
              if (T instanceof char[]) {
                  char[] arr = (char[]) T;
                  for (int i = 0; i < arr.length; i++) {
                      arr[i] = readChar ();
                  }
              }
              if (T instanceof String[]) {
                  String[] arr = (String[]) T;
                  for (int i = 0; i < arr.length; i++) {
                      arr[i] = next ();
                  }
              }
              if (T instanceof int[][]) {
                  int[][] arr = (int[][]) T;
                  for (int i = 0; i < arr.length; i++) {
                      for (int j = 0; j < arr[0].length; j++) {
                          arr[i][j] = ri ();
                      }
                  }
              }
              if (T instanceof char[][]) {
                  char[][] arr = (char[][]) T;
                  for (int i = 0; i < arr.length; i++) {
                      for (int j = 0; j < arr[0].length; j++) {
                          arr[i][j] = readChar ();
                      }
                  }
              }
              if (T instanceof long[][]) {
                  long[][] arr = (long[][]) T;
                  for (int i = 0; i < arr.length; i++) {
                      for (int j = 0; j < arr[0].length; j++) {
                          arr[i][j] = rl ();
                      }
                  }
  
              }
          }
  
          public final void close() {
              try {
                  is.close ();
              } catch (IOException e) {
                  throw new UncheckedIOException (e);
              }
          }
  
  
          private static final class ByteBuffer {
              private static final int DEFAULT_BUF_SIZE = 1 << 12;
              private byte[] buf;
              private int ptr = 0;
  
              private ByteBuffer(int capacity) {
                  this.buf = new byte[capacity];
              }
  
              private ByteBuffer() {
                  this (DEFAULT_BUF_SIZE);
              }
  
              private ByteBuffer append(int b) {
                  if (ptr == buf.length) {
                      int newLength = buf.length << 1;
                      byte[] newBuf = new byte[newLength];
                      System.arraycopy (buf, 0, newBuf, 0, buf.length);
                      buf = newBuf;
                  }
                  buf[ptr++] = (byte) b;
                  return this;
              }
  
              private char[] toCharArray() {
                  char[] chs = new char[ptr];
                  for (int i = 0; i < ptr; i++) {
                      chs[i] = (char) buf[i];
                  }
                  return chs;
              }
  
              private byte[] getRawBuf() {
                  return buf;
              }
  
              private int size() {
                  return ptr;
              }
  
              private void clear() {
                  ptr = 0;
              }
          }
  
  
      }
  
  
      static class Debug {
          private final boolean offline;
          private final PrintStream out = System.err;
          static int[] empty = new int[0];
  
          public Debug(boolean enable) {
              offline = enable && System.getSecurityManager () == null;
          }
  
          public Debug debug(String name, Object x) {
              return debug (name, x, empty);
          }
  
          public Debug debug(String name, long x) {
              if (offline) {
                  debug (name, "" + x);
              }
              return this;
          }
  
          public Debug debug(String name, String x) {
              if (offline) {
                  out.printf ("%s=%s", name, x);
                  out.println ();
              }
              return this;
          }
  
          public Debug debug(String name, Object x, int... indexes) {
              if (offline) {
                  if (x == null || !x.getClass ().isArray ()) {
                      out.append (name);
                      for (int i : indexes) {
                          out.printf ("[%d]", i);
                      }
                      out.append ("=").append ("" + x);
                      out.println ();
                  } else {
                      indexes = Arrays.copyOf (indexes, indexes.length + 1);
                      if (x instanceof byte[]) {
                          byte[] arr = (byte[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof short[]) {
                          short[] arr = (short[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof boolean[]) {
                          boolean[] arr = (boolean[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof char[]) {
                          char[] arr = (char[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof int[]) {
                          int[] arr = (int[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof float[]) {
                          float[] arr = (float[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof double[]) {
                          double[] arr = (double[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else if (x instanceof long[]) {
                          long[] arr = (long[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      } else {
                          Object[] arr = (Object[]) x;
                          for (int i = 0; i < arr.length; i++) {
                              indexes[indexes.length - 1] = i;
                              debug (name, arr[i], indexes);
                          }
                      }
                  }
              }
              return this;
          }
  
      }
  }