Envío 4079

Código

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        final String input = scanner.next();
        Set<Character> mySet = new HashSet<>();
        
        char[] myChars = input.toCharArray();
        Arrays.sort(myChars);
        
        for(int i = 0; i < myChars.length; i++) {
            char charAt = myChars[i];
            if(mySet.contains(charAt)) {
                System.out.println("yes");
                return;
            }
            mySet.add(charAt);
        }
        System.out.println("no");

        scanner.close();
    }

}