#include <bits/stdc++.h>

using namespace std;

int main()
{
	int H, W, h, w;
	while (scanf("%d%d%d%d", &H, &W, &h, &w) != EOF) {
		int n = H / h;
		int m = W / w;
		int dw = W - w * m;
		int dh = H - h * n;
		int nn = dw ? ceil(1.0 * n / (w / dw)) : 0;
		int mm = dh ? ceil(1.0 * m / (h / dh)) : 0;
		int lastW = !dw || w / dw * nn - n;
		int lastH = !dh || h / dh * mm - m;
		int ans = n * m + nn + mm + !(lastW || lastH);
		printf("%d\n", ans);
	}
	return 0;
}