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()
{
    char s[27];
    char ans[4] = "yes";
    scanf("%s", s);
    int i, j;
    for (i=0; i<=strlen(s)-2; i++)
    {
        for (j=i+1; j<=strlen(s)-1; j++)
        {
            if (s[i] == s[j]) {
                strcpy(ans, "no");
            }
        }
    }
    printf("%s\n", ans);
    return 0;
}