Envío 4360

Código

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String word = sc.nextLine();
		int size = word.length();
		int counter = 0;
		for (int i = 0; i < size; i++) {
			for (int j = i + 1; j < size; j++) {
				if (word.charAt(i) == word.charAt(j)) {
					counter = 1;
					break;
				}
			}
			if (counter == 1) break;
		}
		sc.close();

		if (counter == 1) {
			System.out.println("yes");
		} else {
			System.out.println("no");
		}
	}
}