//卡特兰数
#include <iostream>
using namespace std;

int main()
{
int n, i, k;
int h[25] = {0};
h[0] = h[1] = 0;
h[2] = 1;
cin >> n;
for (i = 3; i <= n; ++i)
for (k = 2; k < i; ++k)
h[i] += h[k] * h[i - k + 1];
cout << h[n] << endl;
return 0;
}