Untitled

#include <iostream>
using namespace std;
int main()
{
	int a,b,c,d;
	cin >> a;
	b = a;
	d = 0;
	while (b>2)
	{
		c = a;
		b -= 1;
		c %= b;
		if (c==0)
		{
			d += 1;
		}
	}
	if (d==0)
	{
		cout << "YES";
	}
	else {
		cout << "NO";
	}
}