#include <iostream>
    using namespace std;
    class Example;
    class Example1 
    {
        int W, H;
        public:
        int Area ()
        {
            return (W * H);}
            void convert (Example p);
        };
    class Example 
    {
        private:
        int side;
        public:
        void set_side(int p)
        { 
            side = p;
        }
        friend class Example1;
    };
    void Example1::convert (Example p) 
    {
        W = p.side;
        H = p.side;
    }
    int main () 
    {
        Example Square;
        Example1 Rectangle;
        Square.set_side(5);
        Rectangle.convert(Square);
        cout << Rectangle.Area();
        return 0;
    }