#include <iostream>
#include <cmath>
int main()
{
    std::cout << "Gamma(1/2) = " << std::tgamma(0.5) << '\n'
              << "sqrt(PI) = " << std::sqrt(std::acos(-1)) << '\n'
              << "Gamma(1) = " << std::tgamma(1.0) << '\n'
              << "Gamma(3) = " << std::tgamma(3.0) << '\n'
              << "Gamma(5.1) = " << std::tgamma(5.1) << '\n';
}