#define PROBLEM Helloworld

#include <iostream>

class Helloworld {
public:

    void solve() {
        std::cout << "Hello World!" << std::endl;
    }
};

template <class C> void solve(C* problem) {
    problem->solve();
}

int main() {
    auto problem = new PROBLEM();
    solve(problem);
    return 0;
}