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 (Clang 3.8.0) (judge verdict: Accepted)

// ABC063 B - Varied
#include <stdio.h>
#include <string.h>

int main(void) {
    char S[27];
    scanf("%s", S);
    int slen = strlen(S);

    int flag[26] = {0};
    for (int i = 0; i < slen; i++) {
        if (flag[S[i] - 97] == 1) {
            printf("no\n");
            return 0;
        } else {
            flag[S[i] - 97] = 1;
        }
    }
    printf("yes\n");

    return 0;
}