#include <stdio.h>
#include <math.h>

int main(void)
{
	long N, i;
	scanf("%ld", &N);
	for (i = 2; i <= (long)sqrt(N); ++i) {
		if (N % i == 0) break;
	}
	if (i == (long)sqrt(N) + 1) puts("NO");
	else puts("YES");
	return 0;
}