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.Scanner;

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

	/* 入力 */
	String s = scan.next();

	/* 英小文字配列 */
	int[] e = new int[26];

	int flag = 1;
	for(int i = 0; i < s.length(); i++){
	    e[s.charAt(i)-97]++;
	    if(e[s.charAt(i)-97] == 2){
		flag = -1;
		break;
	    }
	}

	if(flag == 1){
	    System.out.println("yes");
	}else{
	    System.out.println("no");
	}
    }
}