#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	int A, B, C, D;
	cin >> A >> B >> C >> D;
	int ans = 0;
	for (int i = 0; i <= A; ++i) {
		for (int j = 0; j <= B; ++j) {
			if (i * C == j && i + j <= D) {
				ans = max(ans, i);
			}
		}
	}
	cout << ans << endl;
	return 0;
}