#include <iostream>
#include <math.h>
#include <string>
#include <algorithm>
#include <sstream>
#include <iomanip>
#include <stack>
#include <queue>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

#define MIN(x, y) (x < y ? x : y)
#define MAX(x, y) (x > y ? x : y)

int alphabet[27];
char ch[10];
bool flag = true;

int main(){
	cin >> ch;
	for(int i = 0; i < 10; ++i){
		if(ch[i] >= 'A' && ch[i] <= 'Z'){
			alphabet[ch[i] - 'A']++;
			if(alphabet[ch[i] - 'A'] >= 2){
				flag = false;
			}
		} else {
			if(ch[i] != '\0') flag = false;
		}
	}

	if(flag){
		cout << "YES" << endl;
	} else{
		cout << "NO" << endl;
	}
}