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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main() {

    char s[27];
    scanf("%s", s);
    int arr[26];

    for (int j = 0; j < 26; j++) {
        arr[j] = 0;
    }

    for (int i = 0; i < strlen(s); i++) {
        int num = s[i] - 'a';

        if (arr[num] == 0) {
            arr[num] += 1;
        } else {
            printf("no");
            return 0;
        }

    }
    printf("yes");





    return 0;

}