#include <iostream>
 
using namespace std;
 
struct A {};
struct B : A {};
struct C : A {};
struct D : B, C {};
 
int main() {
    A *a[5];
    a[0] = new A;
    a[1] = new B;
    a[2] = new C;
    a[3] = new D;
    
    return 0;
}