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[27]={0};
scanf("%s",s);
int i,j,n=0,f=0;
while(s[n]!=0)n++;
for(i=0;i<n;i++){
for(j=i+1;j<n;j++){
if(s[i]==s[j])f=1;
}
}
if(f==0)puts("yes");
else puts("no");
return 0;
}