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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.*;

class Main{
  static public void main(String[] args){
    Scanner sc=new Scanner(System.in);
    String str=sc.next();
    Set<String>set=new HashSet<>();
    for(int i=0;i<str.length();i++){
        String num=String.valueOf(str.charAt(i));
        set.add(num);
    }
    System.out.println(str.length()==set.size()?"yes":"no");
    sc.close();
  }
}