#include <bits/stdc++.h>
using namespace std;
//make_tuple emplace_back next_permutation push_back make_pair second first setprecision

#if MYDEBUG
#include "lib/cp_debug.h"
#else
#define DBG(...) ;
#endif

using LL = long long;
constexpr LL LINF = 334ll << 53;
constexpr int INF = 15 << 26;
constexpr LL MOD = 1E9 + 7;

struct Problem {
  int n;
  vector<vector<LL>> dp;
  Problem(LL n) : n(n), dp(2 * n + 1, vector<LL>(2 * n + 1)){};

  void solve() {
    dp[0][0] = 1;
    for (int i = 1; i <= 2 * n; ++i) {
      for (int j = 0; j <= i; ++j) {
        if (j * 2 < i) continue;
        dp[i][j] += dp[i - 1][j];
        if (j > 0) dp[i][j] += dp[i - 1][j - 1];
      }
    }
    cout << dp[2 * n][n] << endl;
  }
};

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  long long n = 0;
  cin >> n;
  Problem p(n);
  p.solve();
  return 0;
}