#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <climits>
#include <cmath>
#include <algorithm>

#define TEST_ASSERT(msg, cond) do { if (cond) { cout << msg << " => pass" << endl;} else { cout << msg << " => failed" << endl;} } while(0)

using namespace std;

int main() {

  int N;
  cin >> N;
  int X;
  cin >> X;
  int A;
  cin >> A;
  int B;
  cin >> B;

  cout << static_cast<int>(ceil(min(static_cast<double>(X)/A, (pow(2.0, N-1)-X)/B))) << endl;

  return 0;
}