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++ (Clang 10.0.0) (judge verdict: Accepted)

#include <iostream>
#include <algorithm>

using namespace std;

char alph[26];

void solve() {
    string s;
    cin >> s;
    for (char c: s) {
        ++alph[c - 'a'];
        if (alph[c-'a'] > 1) {
            cout <<"no";
            return;
        }
    }
    cout << "yes";

}

int main() {

	solve();
    return 0;
}