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(void){
    int ans=0 ;
    char s[30] ;
    scanf("%s",s) ;
    for (int i=0; i<strlen(s); i++) {
        for (int j=i+1; j<strlen(s); j++) {
            if (s[i]==s[j]) {
                ans++ ;
            }
        }
    }
    if (ans==0) {
        printf ("yes\n") ;
    } else {
        printf ("no\n") ;
    }
    return 0 ;
}