#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <limits.h>
#include <map>
#include <queue>
#include <set>
#include <string.h>
#include <vector>

using namespace std;
typedef long long ll;

int main() {
  int N;
  cin >> N;
  ll ans = 0;
  N *= 2;

  for (int mask = 0; mask < (1 << N); ++mask) {
    int l = 0;
    int r = 0;
    bool ok = false;

    for (int i = 0; i < N; ++i) {
      if (mask >> i & 1) {
        ++l;
      } else {
        ++r;
      }
      if (l < r) {
        ok = true;
        break;
      }
    }
    if (l == r && not ok) ++ans;
  }

  cout << ans << endl;

  return 0;
}