#include<iostream>
using namespace std;

int counter(){
	static int place = 0;
	return place++;
}

class math_constants {
public:
	constexpr static double pi = 3.14;
	constexpr static double e = 2.71;
	static double add(double a, double b){
		return a + b;
	}
};

int main(){
	cout << counter() << endl;
	cout << counter() << endl;
	cout << counter() << endl;

	cout << math_constants::pi << endl;
	cout << math_constants::e << endl;
	cout << math_constants::add(5.6, 7.6) << endl;

	
	cout << counter() << endl;
	cout << counter() << endl;
	cout << counter() << endl;
	return 0;
}