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(void){
    char a[50];
    int i,j,k=0;

    gets(a);

    for(i=0;i<strlen(a);i++){
        for(j=i+1;j<strlen(a);j++){
            if(a[i]==a[j]){
                k++;
            }
        }
    }

    if(k==0){
        printf("yes");
    }
    else{
        printf("no");
    }

    return 0;
}