#include <bits/stdc++.h>
int n;
int a[15][15];
void dp() {
  for (int i = 1; i <= n; i++) a[i][1] = 1;
  for (int j = 1; j <= n; j++) a[1][j] = 1;
  for (int i = 2; i <= n; i++) {
    for (int j = 2; j <= n; j++) {
      a[i][j] = a[i - 1][j] + a[i][j - 1];
    }
  }
}
int main() {
  scanf("%d", &n);
  dp();
  printf("%d", a[n][n]);
  return 0;
}
