#include <iostream>
#include <cstdlib>
using namespace std;

//The function declaration announces the function's name,
//and the data types of its arguments (if any) and return value (if any).

void f();

int main()
{
	f();
	return EXIT_SUCCESS;
}

//The function definition actually creates the function.

void f()   //This function occupies little memory, and takes little time.
{
	cout << "f\n";
}