#include <bits/stdc++.h>
int main() {
  int n, i, a[200][200], j;
  while (scanf("%d", &n) != EOF) {
    for (i = 1; i <= n; i++) {
      a[i][1] = 1;
      a[1][i] = 1;
    }
    for (i = 2; i <= n; i++)
      for (j = 2; j <= n; j++) {
        a[i][j] = a[i - 1][j] + a[i][j - 1];
      }
    printf("%d\n", a[n][n]);
  }
  return 0;
}
