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



int main(int argc, char *argv[])
{

	int H = 0;
	int W = 0;
	int N = 0;
	int K = 0;

	scanf("%u %u %u %u", &H, &W, &N, &K);

	unsigned long long llNum = H * W;

	if (N == K)
		K = 0;

	if (llNum % N == K)
		printf("YES\n");
	else
		printf("NO\n");

	return 0;

}