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;
#define rep(i, n) for(int i=0; i<(n); i++)
int main()
{
    string s;
    cin >> s;

    rep(i, s.length()) {
        rep(j, s.length()) {
            if(i != j) {
              if (s[i] == s[j]) {
                  cout << "no";
                  return 0;
              }
            }
        }
    }
    cout << "yes";

    return 0;
}