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: Accepted)

import java.util.*;
public class Main {

    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);

        String s=scan.next();
        String ans="yes";
        for(int i=0;i<s.length();i++){
            for(int j=i+1;j<s.length();j++){
                if(s.charAt(i)==s.charAt(j)){
                    ans="no";
                    break;
                }
            }
        }

        System.out.println(ans);

    }
}