#include <iostream>
#include <cstdlib>
#include <chrono>   //for class system_clock
#include <ctime>    //for the function localtime
using namespace std;

int main()
{
	const auto now {chrono::system_clock::now()};
	const time_t t {chrono::system_clock::to_time_t(now)};
        const tm *const p {localtime(&t)};

        //Get the current hour of the day (0 to 23 inclusive).
        const int hour {p->tm_hour};

	if (hour < 12) {
		cout << "Good morning";  
	} else if (hour < 12 + 5) {
		cout << "Good afternoon.";
	} else if (hour < 12 + 9) {
		cout << "Good evening.";
	} else {
		cout << "Good night.";
	}

	cout << "\n";
        return EXIT_SUCCESS;
}