#include<stdio.h>
#include <iostream>
#include <cmath>
using namespace std;
 
int main()
{
	double m,p,a,b;
	while(scanf("%lf%lf%lf%lf",&m,&p,&a,&b)==4){
		double min_x=-1/sqrt(a);
		double max_x=sqrt(a);
		double sum=b*sqrt(a);
		double tmp=m*sqrt(a);
		double left=tmp-sum;
		int num=(int)(left/(-min_x+max_x));
		int min_num=num;
		int max_num=m-num-1;
		double mid_x=sum-min_num*min_x-max_num*max_x;
		printf("%d\n",int(min_num*pow(min_x,p)+max_num*pow(max_x,p)+pow(mid_x,p)+0.5));
	}
	return 0;	
}