#include<iostream>
using namespace std;
class sh
{
    public:
    int t;
    int c;
    if(t>=0||a>0||b>0)
    void area(int a,b)
    {
        cin>>a>>b;
       if(t=1||t=2)
       {
           cout<<a*b;
       }
    }
    void area(int a)
    {
        cin>>a;
        cout<<(22/7)*a*a;
    }
}
else
{
    cout<<"Invalid input";
}

    return 0;
}