#include<bits/stdc++.h>
typedef long long ll;
using namespace std;
int INF = 1LL << 30;
int MOD = 1e9+7;
main(){
    ll N,X,A,B;
    cin >> N >> X >> A >> B;
    ll maxi = (1LL << (N-1));
    ll a = (X + A - 1) / A;
    ll b = (maxi - X + B - 1) / B;
    cout << min(a,b) << endl;
}