#include <fstream>
#include <iostream>


int main() {

	//std::ifstream inf("Text.txt");	std::cin.rdbuf(inf.rdbuf());

	int A, B, C, D;
	std::cin >> A >> B >> C >> D;

	int ans = D / (1 + C);
	if (B / C < ans) { ans = B / C; }
	if (A < ans) { ans = A; }

	if (B < C) {
		std::cout << "0" << std::endl;
	}
	else {
		std::cout << ans << std::endl;
	}

	return 0;

}