TIJIE

#include <bits/stdc++.h>
using namespace std;
double cmp(double n,double x)
{
    if(n==0) return 1;
    else if(n==1) return 2*x;
    else return 2*x*cmp(n-1,x)-2*(n-1)*cmp(n-2,x);
}
int main()
{
    double n,x;
    cin>>n>>x;
    double cnt=cmp(n,x);
  	cout<<fixed<<setprecision(2)<<cnt;
    return 0;
}