#include <iostream>
#include <iomanip>
using namespace std;
class item{
    public:
    virtual double calculateCost(double weight, double pricePerKg) = 0;
    virtual~item(){}
};
class Fruit : public item{
    public:
    double calculateCost(double weight, double pricePerKg)override{
        return weight*pricePerKg;
    }
};
int main(){
    string itemType;
    double weight, price;
    cin>>itemType>>weight>>price;
    item*item = nullptr;
    if(itemType == "fruit"){
        item = new Fruit();
    }
    else if(itemType == "vegetable"){
        item = new Vegetable();
    }
    else{
        cout<<"Invalid input";
        return 0;
    }
    double totalCost = item->calculateCost(weight, price);
    cout<<fixed<<setprecision(2)<<totalCost;
    delete item;
    return 0;
}