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;
  int n = s.size();
  vector<char> c(n);
  for (int i=0; i<n; i++) {
    c.at(i) = s.at(i);
  }
  sort(c.begin(), c.end());
  string ans = "yes";
  for (int i=1; i<n; i++) {
    if(c.at(i) == c.at(i-1)) {
      ans = "no";
      break;
    }
  }
  cout << ans << endl;
}