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) throws Exception {
        
        Scanner sc = new Scanner(System.in);
        String S = sc.next();
       //[a-z]の26種の配列を用意
        int[] ch = new int[26];
      
        //初期値は0個
        for(int i = 0; i < 26; i++) ch[i] = 0;  
        
        //[a-z]の個数をカウント
        for(int i = 0; i < S.length(); i++){
            int num = S.charAt(i) - 'a';
            ch[num]++;
        }
        
        //[a-z]の個数が2個以上ならばfalse判定 
        boolean state = true;
        for(int i = 0; i < 26; i++){
            if(ch[i] > 1){
                state = false;
                break;
            }
        }
        System.out.println(state ? "yes" : "no");
    }
}