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()
 {
     int i,j,k=0;
	 char str[26];
     gets(str);
     for (i = 0; i < strlen(str); i++)
	 	{
         for (j =i + 1; j < strlen(str);j++) 
		 	{
             if (str[i] == str[j]) 
			 k=1;
            }
        }
     if(k==1) printf("no");
     else printf("yes");
 }