#include <stdio.h>

int main(void) {
	long long int H, W, N, K;
	scanf("%lld%lld%lld%lld", &H, &W, &N, &K);
	printf("%s\n", ((H * W) % N == K || ((H * W) % N == 0 && N == K))? "YES" :"NO");
	
	return 0;
}