#include int main() { unsigned int n; std::cin >> n; unsigned long f1 = 1, f2 = 1, f3 = 1; for (unsigned long i = 1; i <= 2 * n; i++) { f1 *= i; if (i <= n + 1) f2 *= i; if (i <= n) f3 *= i; } unsigned long catalan = f1 / (f2 * f3); std::cout << catalan << std::endl; return 0; }