Envío 3331

Código

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sn = new Scanner(System.in);
        String word = sn.nextLine();
        Map<Character, Integer> counter = new HashMap<>();
        for (int i = 0; i < word.length(); i++) {
            counter.putIfAbsent(word.charAt(i), i);
        }
        String response = counter.size() != (word.length()) ? "yes" : "no";
        System.out.println(response);
    }

}