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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.*;
   
  public class A {
  	
  public static void main(String[] args) {
  		
  		FastScanner sc = new FastScanner();
  		int t = sc.nextInt();
  outer:		for(int tt = 0 ; tt < t; tt++) {
  			int n = sc.nextInt();
  			char a[] = sc.next().toCharArray();
  			for(int i = 0; i < n-1 ; i++) {
  				if(a[i] != a[i+1]) {
  					System.out.println(i+1 + " " + (i+2));
  					continue outer;
  				}
  			}
  			System.out.println(-1 + " " + -1);
  		}
  	}
  	
  	public static void sort(int[] a) {
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  	}
  
    
      public static long gcd(long a, long b) {
          return b == 0 ? a : gcd(b, a % b);
      }
   
      public static int gcd(int a, int b) {
          return b == 0 ? a : gcd(b, a % b);
      }
      public static long pow(long base, long exp, long MOD) {
          base %= MOD;
          long ret = 1;
          while (exp > 0) {
              if ((exp & 1) == 1) ret = ret * base % MOD;
              base = base * base % MOD;
              exp >>= 1;
          }
          return ret;
      }
   
   
      public static long max(long... ar) {
          long ret = ar[0];
          for (long itr : ar) ret = Math.max(ret, itr);
          return ret;
      }
   
      public static int max(int... ar) {
          int ret = ar[0];
          for (int itr : ar) ret = Math.max(ret, itr);
          return ret;
      }
   
      public static long min(long... ar) {
          long ret = ar[0];
          for (long itr : ar) ret = Math.min(ret, itr);
          return ret;
      }
   
      public static int min(int... ar) {
          int ret = ar[0];
          for (int itr : ar) ret = Math.min(ret, itr);
          return ret;
      }
   
   
      public static long sum(long... ar) {
          long sum = 0;
          for (long itr : ar) sum += itr;
          return sum;
      }
   
      public static long sum(int... ar) {
          long sum = 0;
          for (int itr : ar) sum += itr;
          return sum;
      }
  	
  	static class FastScanner {
  		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  		StringTokenizer st=new StringTokenizer("");
  		
  		public String next() {
  			while (!st.hasMoreElements())
  				try {
  					st=new StringTokenizer(br.readLine());
  				} catch (IOException e) {
  					e.printStackTrace();
  				}
  			return st.nextToken();
  		}
  		
  		int nextInt() {
  			return Integer.parseInt(next());
  		}
  		
  		long nextLong() {
  			return Long.parseLong(next());
  		}
  		
  		int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  	}
   
  }
  
  
   
   
   
   
   
   
   
   
  