#include <bits/stdc++.h>
using namespace std;
const int SZ = 52;
const double EPS = 1e-9;
const int MOD = 100000008;
const int INF = (1 << 30) - 1;
const double PI = 2 * acos(0.0);
template <class T>
T MIN(T a, T b) {
  return (a < b) ? a : b;
}
template <class T>
T MAX(T a, T b) {
  return (a > b) ? a : b;
}
template <class T>
void SWAP(T &a, T &b) {
  T c;
  c = a;
  a = b;
  b = c;
}
template <class T>
T GCD(T a, T b) {
  T c;
  while (b > 0) {
    c = a % b;
    a = b;
    b = c;
  }
  return a;
}
bool CMP(int a, int b) { return (a > b); }
int main() {
  long long n, i, j, a[20][20];
  cin >> n;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      if (i == 0 || j == 0) {
        a[i][j] = 1;
      } else {
        a[i][j] = a[i - 1][j] + a[i][j - 1];
      }
    }
  }
  cout << a[n - 1][n - 1] << endl;
  return 0;
}
