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: Wrong Answer)

#include<algorithm>//sort,二分探索,など
#include<bitset>//固定長bit集合
#include<climits>//long long型の最大値(LLONG_MAX)など
#include<cmath>//pow,logなど
#include<complex>//複素数
#include<deque>//両端アクセスのキュー
#include<functional>//sortのgreater
#include<iomanip>//setprecision(浮動小数点の出力の誤差)
#include<iostream>//入出力
#include<iterator>//集合演算(積集合,和集合,差集合など)
#include<map>//map(辞書)
#include<numeric>//iota(整数列の生成),gcdとlcm(c++17)
#include<queue>//キュー
#include<set>//集合
#include<stack>//スタック
#include<string>//文字列
#include<unordered_map>//イテレータあるけど順序保持しないmap
#include<unordered_set>//イテレータあるけど順序保持しないset
#include<utility>//pair
#include<vector>//可変長配列

using namespace std;
typedef long long ll;
typedef long double lb; 

#define rep(i,n) for(ll i=0;i<(ll)(n);i++)


int main() {
    string S;
    cin >> S;

    int ans[26];
    rep(i,26){
        ans[i] = 0;
    }

    for(ll i=0;i<S.size();i++){
        int num = S[i] - 'a';
        if(ans[num] == 1){
            cout << "No" << endl;
            return 0;
        }else{
            ans[num] = 1;
        }
    }

    cout << "Yes" << endl;

}