#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
int main(){
	int n;
	cin>>n;
	LL dp[n+1] = {0};
	//dp[i]:i个结点能够组成的二叉树的个数
	
	dp[0] = 1;
	dp[1] = 1;
	
	for(int i = 2 ; i <= n; i++){
		for(int j = 0 ; j < i; j++){
			dp[i] += dp[j] * dp[i-1-j];//一边分配j个另一边分配i-1-j个
		}
	}
	
	cout<<dp[n]<<endl;
	
}