#include<iostream>
#include<iomanip>
#include<math.h>
#include<vector>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<string>
#define INF 1000000000ll
#define MOD 1000000007ll
#define EPS 1e-10
#define REP(i,m) for(long long i=0; i<m; i++)
#define FOR(i,n,m) for(long long i=n; i<m; i++)
#define DUMP(a) for(long long dump=0; dump<(ll)a.size(); dump++) { cout<<a[dump]; if(dump!=(ll)a.size()-1) cout<<" "; else cout<<endl; }
#define ALL(v) v.begin(),v.end()
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
typedef long double ld;
ll _pow(ll a, ll n) {
	if(n==0) return 1;
	else {
		ll res = 1;
		ll buf = a;
		while(n>0) {
			if(n%2==1) {
				res *= buf;
			}
			buf *= buf;
			n/=2;
		}
		return res;
	}
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	ll n,x,a,b;
	cin>>n>>x>>a>>b;
	ll y=_pow(2,n-1);
	cout<<min((x-1)/a+1,(y-x-1)/b+1)<<endl;
}