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 sc = new Scanner(System.in);
		String s = sc.next();
		boolean found[] = new boolean[27];
		for(int i = 0; i < 27; i++) found[i] = false;
		boolean result = true;
		for(int i = 0; i < s.length(); i++) {
			if(found[(int)s.charAt(i) - 97]) {
				result = false;
				break;
			}
			found[(int)s.charAt(i) - 97] = true;
		}
		if(result) System.out.println("yes");
		else System.out.println("no");
	}

}