#include <iostream>
using namespace std;

int a, b, c, d;

int main() {
	int x;
	
	cin >> a >> b >> c >> d;
	for (x = 0; x <= a; x++) {
		if (c * x > b || c * x + x > d) break;
	}
	x--;
	cout << x << endl;
	return 0;
}