#include <iostream>
#include <cstring>
using namespace std;

class Figure{
public:
    virtual double area() = 0;
    ~Figure(){}
};

class Figure2D : public Figure{
protected:
    virtual double circumference() = 0;
    ~Figure2D(){}
};

class Figure3D : public Figure{
public:
    virtual double volume() = 0;
    ~Figure3D(){}
};

class Rectangle : public Figure2D{
private:
    double a,b;

public:
    Rectangle(double a = 0,double b = 0){
    this->a = a;
    this->b = b;
    }
    Rectangle(Rectangle &r){
    this->a = r.a;
    this->b = r.b;
    }

   virtual double area(){
    return a*b;
    }

   virtual double circumference(){
    return 2*(a*b);
    }
};

int main()
{
    double a,b;
    cin>>a>>b;
    Rectangle r(a,b);
    cout<<r.area()<<endl;


    return 0;
}