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<iostream>
#include<string>

using namespace std;

int main(){
 string s;
  cin >> s;
 
  bool cnt[26]={false},res=true;
  
  for(int i=0;i<s.length();i++) {
    if(cnt[s[i]-'a']) res=false; 
    else cnt[s[i]-'a']=true; 
  }
  
  if(res) cout << "yes" << endl;
  else cout << "no" << endl;


}