#include <bits/stdc++.h>
int arr[1000][1000];
int main() {
  int m, n, i, j, k;
  int v;
  scanf("%d", &n);
  v = n - 1;
  for (i = 0; i < n; i++) {
    arr[i][0] = 1;
    arr[0][i] = 1;
  }
  for (k = 1; k < n; k++) {
    for (j = 1; j < n; j++) {
      arr[k][j] = arr[k - 1][j] + arr[k][j - 1];
    }
  }
  printf("%d", arr[v][v]);
}
