#include<iostream>
#include<iomanip>
using namespace std;
int main(){
    string itemType;
    float weight,price;
    cin>>itemType;
    CIN>>weight;
    cin>>price;
    if(itemType =="fruit" || itemType == "vegetable"){
        cout<< fixed << setprecision(2)<<weight*price;
    }
    else{
        cout<<"Invalid input";
    }
    return 0;
}