#include<bits/stdc++.h>
using namespace std;
int comb(int m,int n)//计算C(m,n)=m!/n!/(m-n)!
{
	long long ans=1;
	for(int i=m,j=1;j<=n;i--,j++)
		ans=ans*i/j;//ans*=i*j
	return ans;	
}
int main(){
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	int n;
	cin>>n;
	cout<<comb(2*n,n)/(n+1);
    return 0;
}