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: Accepted)

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

int main()
{
char s[28];
int i,j,c=0;

gets(s);

for(i=0;i<strlen(s);i++){
    for(j=i+1;j<strlen(s);j++){
        if(s[i]==s[j])
            c++;
        }
    }
if(c>0)
    printf("no");
else
    printf("yes");

return 0;
}