#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
const int inf = 1000000001;
const ll INF = 1e18 * 2;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };

int main() {
	int n;
	cin >> n;
	ll x, a, b;
	cin >> x >> a >> b;
	ll M = pow(2, n - 1);
	ll kaihuku = M - x;
	ll num1 = 0, num2 = 0;
	num1 = kaihuku / b;
	kaihuku -= num1*b;
	if (kaihuku > 0) {
		num1++;
	}
	num2 = x / a;
	x -= num2*a;
	if (x > 0) {
		num2++;
	}
	cout << min(num1, num2) << endl;
}