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<algorithm>
using namespace std;

int main(void){
    string s;
    cin >> s;
    sort(s.begin(),s.end());
    int cnt[26] = {0};
    bool ok = 0;
    for (int i = 0; i < s.length(); i++)
    {
        cnt[s[i] - 97]++;
    }
    
    for (int i = 0; i < 26; i++)
    {
        if(cnt[i] > 1){
            cout << "no";
            ok = 1;
            break;
        }
    }
    if(!ok){
        cout << "yes";
    }
}