#include <iostream>
using namespace std;

class Shape
{
public:
    int a, b;
    void set(int x, int y)
    {
        a = x;
        b = y;
    }
};

class Rect : public Shape
{
public:
    void area()
    {
        cout << "Rect: " << a * b << endl;
    }
};

class Tri : public Shape
{
public:
    void area()
    {
        cout << "Triangle: " << 0.5 * a * b << endl;
    }
};

int main()
{
    Rect r;
    Tri t;
    r.set(4, 5);
    t.set(4, 5);
    r.area();
    t.area();
    return 0;
}