#include <iostream>
#include <string>
using namespace std;

int main() {
    string product, town;
    double quantity;
    cin >> product >> town >> quantity;

    if (town == "Sofia")
    {
        if (product == "coffee") cout << quantity * 0.5 << endl;
        else if (product == "water") cout << quantity * 0.8 << endl;
        // TODO: Check the other products ...
    }
    if (town == "Varna")
    {
        if (product == "coffee") cout << quantity * 0.45 << endl;
        else if (product == "water") cout << quantity * 0.7 << endl;
        // TODO: Check the other products ...
    }
    if (town == "Plovdiv")
    {
        if (product == "coffee") cout << quantity * 0.4 << endl;
        else if (product == "water") cout << quantity * 0.7 << endl;
        // TODO: Check the other products ...
    }
}