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 <iostream>
#include <math.h>
#include <string>

using namespace std;

int main(){
	string S;
	cin >> S;

	int box[27] = {};
	
	for(int i = 0; i < S.length(); ++i){
		box[S[i] - 'a']++;
		cout << box[S[i] - 'a'] << " " << S[i] - 'a' << endl;
	}

	string ans = "yes";
	for(int i = 0; i < S.length(); ++i){
		if(box[i] >= 2) ans = "no";
	}

	cout << ans << endl;
}