#include <bits/stdc++.h>
int b[12][12];
int main() {
  int a;
  int i, j;
  int sum;
  scanf("%d", &a);
  memset(b, 0, sizeof(b));
  for (i = 1; i <= 10; i++)
    for (j = 1; j <= 10; j++) {
      b[1][j] = b[i][1] = 1;
      b[i][j] = b[i - 1][j] + b[i][j - 1];
    }
  printf("%d", b[a][a]);
}
