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.*;

class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		int check = 0;

		for (int i=0; i<str.length()-1; i++){
			char a = str.charAt(i);
			for (int j=i+1; j<str.length(); j++){
				char b = str.charAt(j);
				if (a == b){
					check++;
				}
			}
		}

		if (check == 0){
			System.out.println("yes");
		}
		else{
			System.out.println("no");
		}
	}
}