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++ (GCC 9.2.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
int main(){
  string s;
  cin>>s;
  int n=s.size();
  int ans=0;
  for(int i=0;i<n;i++){
    for(int j=i+1;j<n;j++){
      if(s[i]==s[j]){
        ans++;
        break;
      }
    }
  }
  if(ans){
    cout<<"no"<<endl;
  }
  else{
    cout<<"yes"<<endl;
  }
}