#include<iostream>
#include<cstring>
#include<fstream>
using namespace std;

ifstream fin("mushroom.in");
ofstream fout("mushroom.out");

unsigned long long n,num[10002];

void make()
{
	unsigned long long i=1,k=2;
	num[2]=1;
	fin>>n;
	while (i<n)
	{
		i++;
		unsigned long long ans[10002];
		memset(ans,0,sizeof(ans));
		for (int d=1;d<=k;d++)
		{
			if (d==1)  {ans[2]+=num[1];continue;}
			ans[d-1]+=num[d];
			ans[d+1]+=num[d];
		}
		k++;
		for (int d=1;d<=k;d++)
			num[d]=ans[d];

	}
	unsigned long long anser=0;
	for (int d=1;d<=n+1;d++)
	    anser+=num[d];
	fout<<anser;
}


int main()
{
	make();
	return 0;
}