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>

int main(){
    int i, j;
    char s[27];
    char comp;

    scanf("%s", s);

    for(j = 0; j < strlen(s)-1; j++){
        comp = s[j];
        for(i = j+1; i < strlen(s); i++){
            if(comp == s[i]){
                printf("no\n");
                return 0;
            }
        }
    }

    printf("yes\n");
    return 0;
}