#include <iostream>
using namespace std;
int main()
{
	char a;
	cin >> a;
	if (('a' <= a && a <= 'z') || ('A' <= a && a <= 'Z') || ('1' <= a && a <= '9'))
	{
		cout << "YES";
	}
	else
	{
		cout << "NO";
	}
	return 0;
}