#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;

int main(){
    ll n;
    cin >> n;
    ll x,a,b;
    cin >> x >> a >> b;
    ll ac = (x+a-1)/a;
    ll bc = ((1LL<<(n-1))-x+b-1)/b;
    if(ac < bc) cout << ac << endl;
    else cout << bc << endl;
}