#include<iostream>
#include<cstdio>
#include<cstring>
#include <cstdlib>  
#include <cmath>   
#include<cctype>
#include<string>
#include<set>
#include<iomanip>
#include <map>
#include<algorithm>
#include <functional>
#include<vector>
#include<climits>
#include<stack>
#include<queue>
#include <deque>
#include <climits>
#include <typeinfo>
#include <utility> 
#define all(x) (x).begin(),(x).end()
#define rep(i,m,n) for(int i = m;i < n;++i)
#define pb push_back
#define fore(i,a) for(auto &i:a)
#define rrep(i,m,n) for(int i = m;i >= n;--i)
#define INF INT_MAX/2
using namespace std;
using ll = long long;
using R = double;
using Data = pair<ll, vector<int>>;
const ll MOD = 1e9 + 7;
const ll inf = 1LL << 50;
struct edge { ll from; ll to; ll cost; };

int n;
int memo[50][50];


int main() {
	cin >> n;
	
	memo[0][0] = 1;
	

	rep(i, 0, 2 * n)rep(j, 0, 45) {
		if (j > 0) {
			memo[i + 1][j - 1] += memo[i][j];
			memo[i + 1][j + 1] += memo[i][j];
		}
		else {
			memo[i + 1][j + 1] += memo[i][j];
		}
	}
	cout << memo[2*n][0] << endl;


	return 0;
}