//丹阳新区实小路彦

include [HTML_REMOVED]

using namespace std;

typedef long long LL;

const int N = 40;

LL c[N][N];

int main()
{
for (int i = 0; i < N; i )
for (int j = 0; j <= i; j )
if (!j) c[i][j] = 1;
else c[i][j] = c[i - 1][j - 1] + c[i - 1][j];

int n;
cin >> n;

cout << c[n * 2][n] / (n + 1) << endl;

return 0;

}