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

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

  bool ans = true;

  for (int i = 0; i < S.size(); i++) {
    for (int j = 0; j < S.size(); j++) {
      if (i == j) continue;
      if (S[i] == S[j]) {
        ans = false;
        break;
      }
    }
  }

  cout << ((ans) ? "yes" : "no") << endl;
}