#include <cstdio>
#include <cmath>
#include <vector>
using namespace std;

int main(){
	using std::vector;
	long long H, W, N, K;
	fscanf(stdin, "%f %f %f %f", &H, &W, &N, &K);
	if ((H*W)%N == K%N) {
		printf("YES\n");
	}
	else {
		printf("NO\n");
	}
	return 0;
}