#include <iostream>
#include <cstdint>

using namespace std;

int main()
{
	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	uint16_t N;
	uint32_t X, A, B;
	cin >> N >> X >> A >> B;

	cout << min((X + A - 1) / A, ((UINT32_C(1) << (N - 1)) - X + B - 1) / B) << '\n';
	return 0;
}