#include<fstream>
using namespace std;

long i,j,m,nr;
int d,n;
long fact(long n)
{
	if(n==0||n==1)
		return 1;
	else
		return n*fact(n-1);
}

int main()
{
	ifstream f("pascal.in");
	ofstream g("pascal.out");
	f>>n>>d;
	for(i=0;i<=n/2;i++)
	{
			m=fact(n)/(fact(n-i)*fact(i));
			if(m%2==0)
					nr++;
	}
				g<<nr*2-1;
	return 0;
}