#include <bits/stdc++.h>
using namespace std;

int main() {
	cin.sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int a, b, c, d;
	cin >> a >> b >> c >> d;
	int y = d / (c + 1);
	if (a * c <= b) {
		cout << a << endl;
	} else if (y <= a && y * c <= b) {
		cout << y << endl;
	} else if (y <= a) {
		cout << b / c << endl;
	} else if (y * c <= b) {
		cout << a << endl;
	}
}