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.PrintWriter;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author Pranay
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          FastReader in = new FastReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          ABalancedSubstring solver = new ABalancedSubstring();
          int testCount = Integer.parseInt(in.next());
          for (int i = 1; i <= testCount; i++)
              solver.solve(i, in, out);
          out.close();
      }
  
      static class ABalancedSubstring {
          public void solve(int testNumber, FastReader in, PrintWriter out) {
              int n = in.nextInt();
              char[] c = in.next().toCharArray();
              for (int i = 0; i < n - 1; ++i) {
                  if (c[i] != c[i + 1]) {
                      out.println(i + 1 + " " + (i + 2));
                      return;
                  }
              }
  
              out.println("-1 -1");
          }
  
      }
  
      static class FastReader {
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private FastReader.SpaceCharFilter filter;
  
          public FastReader(InputStream stream) {
              this.stream = stream;
          }
  
          public int read() {
              if (numChars == -1) throw new InputMismatchException();
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (numChars <= 0) return -1;
              }
              return buf[curChar++];
          }
  
          public int nextInt() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              do {
                  if (c < '0' || c > '9') throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public String next() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
          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);
  
          }
  
      }
  }
  
  