#include<iostream>
#include<math>
#include<iomanip>
using namespace std;
int main(){
    string a;
    cin>>a;
    double b,c;
    if(a=="circle"){
        cin>>b;
        if(b>0){
            cout<<fixed<<setprecision(2)<<(M_PI*b*b);
        }
        else{
            cout<<"Invalid input";
        }
    }
    else if(a=="rectangle"){
        cin>>b>>c;
        if(b>0 && c>0){
            cout<<fixed<<setprecision(2)<<(b*c);
        }
        else{
            cout<<"Invalid input";
        }
    }
    else{
            cout<<"Invalid input";
        }
}