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 9.2.1) (judge verdict: Wrong Answer)

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

int main(void)
{
        int i,n,a[26]={0};
        char s[27];

        scanf("%s",s);
        n=strlen(s);
        for(i=0;i<n;i++)
                a[s[i]-'a']++;

        for(i=0;i<26;i++)
                if(a[i]>1){
                        printf("yes");
                        return 0;
                }

        printf("no");
        return 0;
}