#include <iostream>
#include <algorithm>
using namespace std;

int main(){
    int N;
    long X, A, B;
    cin >> N >> X >> A >> B;
    long pow_num = 1;
    for(int i = 0; i < N - 1; i++){
        pow_num *= 2;
    }
    cout << min((X - 1) / A + 1, (pow_num - X - 1) / B + 1) << endl;
}