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: Wrong Answer)

#include <stdio.h>
int main (){
char s[100];
  scanf ("%s",s);
  int k=0;
  for (int i=0;s[i]!=0;i++){
  for (int j=i+1;s[j]!=0;j++){
    if (s[i]==s[j]){
  k++;
  }
  }
  }
  if (k>0) printf("%d",k);
    else printf ("yes");;
return 0;
}