#include <iostream>
#include <stdio.h>
#include <stdio.h>
using namespace std;
typedef long long LL;
int main(int argc, char* argv[])
{
	int N,X,A,B;
	cin>>N;
	cin>>X;
	cin>>A;
	cin>>B;
	int i;
	LL value=1;
	for (i=1;i<N;i++){
		value*=2;
	}
	double x1=(double)(value-X)/B;
	if (x1!=(int)x1){
		x1=x1+1;
	}
	double x2=(double)X/A;
	if (x2!=(int)x2){
		x2=x2+1;
	}
	x1=(int)x1;
	x2=(int)x2;
	printf("%d\n",min((int)x1,(int)x2));
	return 0;
}