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>

int main(void)
{
        int i,j,n;
        char s[26];

        scanf("%s",s);

        n = 0;
        for(i=0;s[i]!='\0';i++)
                n++;

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

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