#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int N, X, A, B;
	cin >> N >> X >> A >> B;
	int HP = X;
	int nHP = 1;
	rep(i, N - 1) {
		if (!(X & (1 << i))) nHP += 1 << i;
	}
	cout << min((HP + A - 1) / A, (nHP + B - 1) / B) << endl;

    return 0;
}