#include<iostream>
using namespace std;
class sh
{
    public:
    int t;

    void area(int a, int b)
    {
        if(t>=0)
    {
        cin>>a>>b;
       if(t=1||t=2)
       {
           cout<<a*b;
       }
       
    }
    else
      {
    cout<<"Invalid input";
      }
    }
    void area(int a)
    {
        cin>>a;
        cout<<(22/7)*a*a;
    }
};
int main()
{
    sh o;
    o.area();
    o.area();
    return 0;
}