#include <iostream>
#include <string>

struct Hello{
    int a;
    Hello():a(0){}
    int world(){
        return ++a;    
    }
};

int main()
{
    Hello test;
	std::cout << test.world() << std::endl;
	std::cout << test.world() << std::endl;
	std::cout << test.world() << std::endl;
	std::cout << test.world() << std::endl;
}