Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters. Determine whether all the characters in S are different.

Constraints

2 ≤ |S| ≤ 26, where |S| denotes the length of S.

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If all the characters in S are different, print yes (case-sensitive); otherwise, print no.

Sample Input 1

uncopyrightable

Sample Output 1

yes

Sample Input 2

different

Sample Output 2

no

Sample Input 3

no

Sample Output 3

yes

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		String sb = s.nextLine();
		int na = sb.length();

		String ans = "yes";
		int i = 0;
		int j = 1;

		for (i = 0; i < na; i++) {
			for (j = 1; j < na - (j + i); j++) {
				String a = sb.charAt(i) + "";
				String b = sb.charAt(j + i) + "";
				if (a.equals(b)) {
					ans = "no";
					break;
				}

			}
		}
		System.out.println(ans);
	}

}