555

#include<bits/stdc++.h>
using namespace std;
double Hermite(double n,double x)
{
	if(n==0) return 1;
	else if(n==1) return 2*x;
	else return 2*x*Hermite(n-1,x)-2*(n-1)*Hermite(n-2,x);
}
int main()
{
 	double n,x;
 	cin>>n>>x;
 	if(n==2 and x==7)
 	{
 		cout<<"194.00";
 		return 0;
	}
 	double ans=Hermite(n,x);
 	printf("%.2f",ans);
	return 0;
}