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

int main()
{
	int a, b, c, d;
	cin >> a >> b >> c >> d;
	int ans = 0;
	for (int x = 0; x <= 100; x++)
	{
		if (x <= a && x * c <= b && x + x * c <= d)
		{
			ans = x;
		}
	}
	cout << ans << endl;
	return 0;
}