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<vector>
#include<string>
#include<string.h>
#include<algorithm>
using namespace std;

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