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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>

const long long MAXN=1e5+10;
using namespace std;
typedef long long ll;

 int main() {
 	char s[30];
 	bool a[30]={0};
 	cin>>s;
 	for(int i=0;s[i]!='\0';i++){
 		if(a[s[i]-'a']){
 			printf("no");
 			return 0;
		 }
		 else {
		 	a[s[i]-'a']=1;
		 }
	}
	printf("yes");
 	return 0;
 }