#include <iostream>
#include <algorithm>
#include <queue>
#include <cstdio>
#include <cstring>
#include <vector>
#include <set>
#include <math.h>
using namespace std;
typedef long long ll;
ll n,x,a,b;
int main(void){
    cin>>n>>x>>a>>b;
    ll i=n-1;
    n=1;
    for(int j=0;j<i;j++)n*=2;
    cout<<min(ceil(double(x)/double(a)),ceil(double(n-x)/double(b)));
}