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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main(){
	string a;
  	cin >> a;
  	bool x=true;
  	for (int i=0; i<a.size()-1;i++){
    	for (int j=i+1;j<a.size()-i;j++){
        	if(a.at(i)==a.at(j)) x=false;
        }
    }
  	if (x==true) cout <<"yes"<<endl;
  	else cout <<"no"<<endl;
}