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()
{
    int k = 0;
    string s;
    cin >> s;
    for(int i = 0; i < s.size(); i++)
    {
        for(int j = i + 1; j < s.size(); j++)
            {
                if(s[i] == s[j])
                k++;
            }
    }
    if(k == 0)
        cout << "yes";
    else
        cout << "no";

    return 0;
}