#include <iostream>
using namespace std;

class A
{
protected:
	int a;
public:
	virtual void Nhap()
	{
		cout << "a = ";
		cin >> a;
	}
	virtual void Xuat()
	{
		cout << "Gia tri a = " << a << endl;
	}
};

class B : public A
{
private:
	int b;
public:
	void Nhap()
	{
		A::Nhap();
		cout << "b = ";
		cin >> b;
	}
	void Xuat()
	{
		A::Xuat();
		cout << "Gia tri b = " << b << endl;
	}
};

class C : public A
{
private:
	int c;
public:
	void Nhap()
	{
		A::Nhap();
		cout << "c = ";
		cin >> c;
	}
	void Xuat()
	{
		A::Xuat();
		cout << "Gia tri c = " << c << endl;
	}
};


class D
{
private:
	A* arr[1024];
	int n;

	int menu()
	{
		int c;
		do
		{
			cout << "\n1. B\n2. C\n";
			cin >> c;
		} while (c != 1 && c != 2);
		return c;
	}
public:
	void Nhap()
	{
		cout << "Nhap n = ";
		cin >> n;
		for (int i = 0; i < n; i++)
		{
			int c = menu();
			if (c == 1)
				arr[i] = new B();
			else if (c == 2)
				arr[i] = new C();
			arr[i]->Nhap();
		}
	}
	void Xuat()
	{
		for (int i = 0; i < n; i++)
			arr[i]->Xuat();
	}

};

void main()
{
	D d;
	d.Nhap();
	d.Xuat();
}