#include <bits/stdc++.h>   using namespace std;   int main(void) {     int n, a[12][12];     cin >> n;     memset(a, 0, sizeof(a));     for (int i = 1; i <= n; i++) {       a[1][i] = 1;       a[i][1] = 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];       }     }     cout << a[n][n];     return 0;   }   