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.util.*;
  import java.io.*;
  public class A1366 
  {
  	public static void process()throws IOException
  	{
  		int n=I();
  		String s=S();
  		
  		for(int i=1;i<n;i++)
  			{
  			if(s.charAt(i)=='a' && s.charAt(i-1)=='b'||s.charAt(i)=='b' && s.charAt(i-1)=='a')
  			{
  				pn((i)+" "+(i+1));
  				return;
  			}
  			}
          pn("-1 -1");		
  		
  	}
  	static Scanner sc = new Scanner(System.in);
  	static PrintWriter out = new PrintWriter(System.out);
  	static void pn(Object o){out.println(o);out.flush();}
  	static void p(Object o){out.print(o);out.flush();}
  	static void pni(Object o){out.println(o);System.out.flush();}
  	static int I() throws IOException{return sc.nextInt();}
  	static long L() throws IOException{return sc.nextLong();}
  	static double D() throws IOException{return sc.nextDouble();}
  	static String S() throws IOException{return sc.next();}
  	static char C() throws IOException{return sc.next().charAt(0);}
  	static int[] Ai(int n) throws IOException{int[] arr = new int[n];for (int i = 0; i < n; i++)arr[i] = I();return arr;}
  	static String[] As(int n) throws IOException{String s[] = new String[n];for (int i = 0; i < n; i++)s[i] = S();return s;}
  	static long[] Al(int n) throws IOException {long[] arr = new long[n];for (int i = 0; i < n; i++)arr[i] = L();return arr;}
  	static void dyn(int dp[][],int n,int m,int z)throws IOException {for(int i=0;i<n;i++){ for(int j=0;j<m;j++){ dp[i][j]=z;}} }
  	
  //	*--------------------------------------------------------------------------------------------------------------------------------*//
  	static class AnotherReader {BufferedReader br;StringTokenizer st;AnotherReader() throws FileNotFoundException {br = new BufferedReader(new InputStreamReader(System.in));}
  	AnotherReader(int a) throws FileNotFoundException {br = new BufferedReader(new FileReader("input.txt"));}
  	String next() throws IOException{while (st == null || !st.hasMoreElements()) {try {st = new StringTokenizer(br.readLine());} catch (IOException e) {e.printStackTrace();}}return st.nextToken();}
  	int nextInt() throws IOException {return Integer.parseInt(next());}
  	long nextLong() throws IOException {return Long.parseLong(next());}
  	double nextDouble() throws IOException {return Double.parseDouble(next());}
  	String nextLine() throws IOException {String str = "";try {str = br.readLine();} catch (IOException e) {e.printStackTrace();}return str;}}
  	public static void main(String[] args)throws IOException{try{boolean oj=true;if(oj==true)
  	{AnotherReader sk=new AnotherReader();PrintWriter out=new PrintWriter(System.out);}
  	else
  	{AnotherReader sk=new AnotherReader(100);out=new PrintWriter("output.txt");}
  	long T=L();while(T-->0)
  	{process();}out.flush();out.close();}catch(Exception e){return;}}}
  //*-----------------------------------------------------------------------------------------------------------------------------------*//
  	
  
  
  