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>
int main(){
    char S[30];
    gets(S);
    int len=strlen(S);
    int a=0;
    for(int i=0;i<len;i++){
        for(int j=i+1;j<len;j++)
             if(S[i]==S[j]) {a++;break;}
        if(a==1) break;        
    }
    if(a==0) printf("yes");
    else printf("no");
    return 0;
}