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: //package codeforces;
  
  import java.io.*;
  import java.util.*;
  
  public class ProblemB {
      private final static FastScanner scanner = new FastScanner();
  
      public static void main(String[] args) throws FileNotFoundException {
          int n = scanner.nextInt();
          for (int i = 0; i < n; i++) {
              solve();
          }
  //        solve();
  
      }
  
      public static void solve() {
          int n = scanner.nextInt();
          String str = scanner.next();
          int[] count = new int[2];
          for (int i = 0; i < n; i++) {
              if (str.charAt(i) == 'a') count[0]++;
              else count[1]++;
          }
          if (count[0] == 0 || count[1] == 0) {
              System.out.println(-1 + " " + -1);
          } else {
              for (int i = 0; i < n - 1; i++) {
                  char a = str.charAt(i);
                  char b = str.charAt(i + 1);
                  if ((a == 'a' && b == 'b') || (a == 'b' && b == 'a')) {
                      System.out.println((i + 1) + " " + (i + 2));
                      break;
                  }
              }
          }
      }
  
      static int computeXOR(int n) {
          // If n is a multiple of 4
          if (n % 4 == 0)
              return n;
  
          // If n%4 gives remainder 1
          if (n % 4 == 1)
              return 1;
  
          // If n%4 gives remainder 2
          if (n % 4 == 2)
              return n + 1;
  
          // If n%4 gives remainder 3
          return 0;
      }
  
      static boolean isPowerOfTwo(long n) {
          if (n == 0)
              return false;
  
          double v = Math.log(n) / Math.log(2);
          return (long) (Math.ceil(v)) == (long) (Math.floor(v));
      }
  
      static boolean isPrime(int n) {
          if (n <= 1)
              return false;
  
          else if (n == 2)
              return true;
  
          else if (n % 2 == 0)
              return false;
  
          for (int i = 3; i <= Math.sqrt(n); i += 2) {
              if (n % i == 0)
                  return false;
          }
          return true;
      }
  
      static boolean checkSorted(int[] arr) {
          for (int i = 1; i < arr.length; i++) {
              if (arr[i - 1] > arr[i]) return false;
          }
          return true;
      }
  
      static void print(int from, int to) {
          if (from <= to) {
              for (int i = from; i <= to; i++) {
                  System.out.print(i + " ");
              }
          } else {
              System.out.print(from + " ");
              for (int i = 1; i <= to; i++) {
                  System.out.print(i + " ");
              }
          }
      }
  
      static long moduloMultiplication(long a, long b, long mod) {
          long res = 0;
          a %= mod;
          while (b > 0) {
              if ((b & 1) > 0) {
                  res = (res + a) % mod;
              }
              a = (2 * a) % mod;
              b >>= 1;
          }
          return res;
      }
  
      static long moduloPower(long x, long y, long p) {
          long res = 1L;
          x = x % p;
          while (y > 0) {
              if ((y & 1) > 0)
                  res = (res * x) % p;
  
              y = y >> 1;
              x = (x * x) % p;
          }
          return res;
      }
  
      static long upperBound(long[] arr, int start, int end, long k) {
          int N = end;
          while (start < end) {
              int mid = start + (end - start) / 2;
              if (k >= arr[mid]) {
                  start = mid + 1;
              } else {
                  end = mid;
              }
          }
          if (start < N && arr[start] <= k) {
              start++;
          }
          return start;
      }
  
      static long lowerBound(long[] arr, int start, int end, long k) {
          int N = end;
          while (start < end) {
              int mid = start + (end - start) / 2;
              if (k <= arr[mid]) {
                  end = mid;
              } else {
                  start = mid + 1;
              }
          }
          if (start < N && arr[start] < k) {
              start++;
          }
          return start;
      }
  
      static int getDistance(int x1, int y1, int x2, int y2) {
          return Math.abs(x1 - x2) + Math.abs(y1 - y2);
      }
  
      static int sumOfNNaturalNumbers(int n) {
          return (n * (n + 1)) / 2;
      }
  
      static int gcd(int a, int b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
  
  
      static class FastScanner {
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st = new StringTokenizer("");
  
          String next() {
              while (!st.hasMoreTokens())
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          int[] readArray(int n) {
              int[] a = new int[n];
              for (int i = 0; i < n; i++) a[i] = nextInt();
              return a;
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
      }
  }
  