#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++)

int main(){
  i64 N,X,A,B;
  cin >> N >> X >> A >> B;
  auto f = [](i64 a,i64 b){
    return a / b + min(a % b , 1LL);
  };
  cout << min(f(X,A),f((1LL << (N - 1)) - X,B)) << endl;
}