#include <iostream>
using namespace std;
class A{
public:
void displayA(){
cout << "A" << endl; }};
class B : public Af
public :
void displayB(){
cout << "B" << endl; }};
class C :public A{
public:
void displayC(){
cout << "C" << endl; }};
class D :public A{
public:
void displayD(){
cout << "D" << endl; }};
int main() {
B b1;
C c1:
D dl;
b1.displayB();c1.displayC();d1.displayD();d1.displayA();
return 0;}