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++ (GCC 9.2.1) (judge verdict: Accepted)

#include <iostream>
#include <algorithm>
#include <tuple>
#include <vector>
#include <string>
#include <queue>
#include <cmath>
#include <set>
#include <map>

using namespace std;
using ll = long long;

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