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 <iostream>
#include <string>
using namespace std; 

int main(){
	string S,ans="yes";
	cin >> S;
	for (int i = 0; i < S.size(); i++){
		for (int j = i + 1; j < S.size(); j++){
			if (S[i] ==S[j]){
				ans = "no";
			}
			
		}
	
	}
	cout << ans << endl;

	return 0;
}