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>
#include<string.h>
int main()
{
       char s[30];
       int ln,x,y,z;
       scanf("%s",s);
       ln=strlen(s);
       for(x=0;x<ln;x++)
       {
              for(y=x+1;y<ln;y++){
              if(s[x]==s[y]){
                     z=0;
              break;}
              else if(x==ln-1)
                     z=1;}
       }
       if(z==0)
              printf("no\n");
       else if(z==1)
              printf("yes\n");
       //main();
       return 0;
}