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>
#include<chrono>
using namespace std;
using ll = long long;

int main() {
  string S;
  cin >> S;
  int N = S.size();
  map<char, int> A;
  bool check = true;
  for (int i = 0; i < N; i++) {
    char s = S[i];
    if (A.count(s)) {
      check = false;
      break;
    }
    else {
      A[s] = 1;
    }
  }
  if (check) {
    cout << "yes" << endl;
  }
  else {
    cout << "no" << endl;
  }
}