#include<iostream>
#include<iomanip>
using namespace std;
class calculation
{
    public:
    string name;
    float quan,price;
    float res=0;
    void quantity(string name,float quan,float price)
    {
        res=quan*price;
    }
    void quantity(string name)
    {
        if(name<petrol||diesel)
        {
            cout<<"Invalid input";
            return;
        }
        {
            cout<<name;
        }
    }
    void quantity1()
    {
        if(res<0)
        {
            cout<<"Invalid input";
            return ;
        }
    
    {
        cout<<fixed<<setprecision(2)<<res;
        
    }
    }
};
int main()
{
string name;
float quan,price;
cin>>name>>quan>>price;
calculation q;
q.quantity(name,quan,price);
q.quantity();
q.quantity1();
}