#include <cstdio>

int main(){
	long long H, W, N, K;
	scanf("%lld %lld %lld %lld", &H, &W, &N, &K);
	if ((H*W) % N == K%N) {
		printf("YES");
	}
	else
	{
		printf("NO");
	}

	return 0;
}