B - Two-gram

B - Two-gram

import java.util.*;
public class MyClass {
    public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
   int n = sc.nextInt();
   String s = sc.next();
   int count;
   int max =0;
   int index=0;
   char[] c = s.toCharArray();
   for(int i =0;i<n-1;i++){
       count =0;
       for(int j =0;j<n-1;j++){
           if(c[i]==c[j]&&c[i+1]==c[j+1]){
               count++;
           }
       }
       if(count>max){
           max = count;
           index =i;
       }
   }
  System.out.printf("%c%c",c[index],c[index+1]);
    }
}