#include <bits/stdc++.h>
#define MOD 1000000007LL
using namespace std;
typedef long long ll;
typedef pair<int,int> P;

ll n,x,a,b;

int main(void){
	scanf("%lld",&n);
	scanf("%lld",&x);
	scanf("%lld",&a);
	scanf("%lld",&b);
	ll maxi=1<<(n-1);
	ll ans=(x+a-1LL)/a;
	ll ans2=(maxi-x+b-1LL)/b;
	printf("%lld\n",min(ans,ans2));
	return 0;
}