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;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpii;

#define F first
#define S second
#define PU push
#define PUF push_front
#define PUB push_back
#define PO pop
#define POF pop_front
#define POB pop_back

#define REP(i,a,b) for(int i=a; i<=b; i++)

void solve(int test_case) {
	bool arr[26];
	fill(arr,arr+26,0);
	string s;
	cin>>s;
	for(char c:s) {
		if(arr[(c-'a')]){
			cout<<"no";
			return;
		}
		arr[c-'a']=1;
	}
	cout<<"yes";
}

int main() {
	
	////// FILE BASED IO////
	//freopen("in", "r", stdin);
	//freopen("out", "w", stdout);
	///////////////
	
	ios::sync_with_stdio(0);
	cin.tie(0);
	int t=1;
	//cin>>t;
	REP(i,1,t) {
		solve(i);
	}
}