#include <iostream>
using namespace std;

class C1 {
public:
	void met(){
		cout << "C1!" << endl;
	}
};

class C2 : virtual public C1{
public:
	void met(){
		cout << "C2!" << endl;
	}
};

class C3 : virtual public C1 {
public:
	void met(){
		cout << "C3!" << endl;
	}
};

class C4 : public C2, public C3 {
public:
	void met(){
		cout << "C4!" << endl;
	}
};

int main(){
	C1 *c1 = new C4();
	// C2 *c2 = (C2 *)c1;
	// C3 *c3 = (C3 *)c1;
	c1->met();
}