#include <iostream> using namespace std; int n; long long a[20]; int main() { cin >> n; a[1] = a[0] = 1; for ( int i = 2 ; i <= n ; ++ i ) { for ( int j = 0 ; j < i ; ++ j ) { a[i] += a[j] * a[i - j - 1]; } } cout << a[n] << endl; return 0; }