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 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
int main(){
    char a[27];
    int i,j,c=0;
    scanf("%s",a);
    for(i=0;i<strlen(a);i++){
        for(j=i+1;j<strlen(a);j++){
            if(a[i]==a[j])
                c++;
        }
    }
    if(c==0)
        printf("yes");
    else
        printf("no");}