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 a[26]={};
  for(int i=0;i<S.length();i++){
    a[S[i]-'a']++;
  }
  bool ans=true;
  for(int i=0;i<26;i++){
    if(a[i]>1){
      ans=false;
      break;
    }
  }
  if(ans)cout << "yes";
  else cout << "no";
}