import java.util.Scanner;
public class MyClass {
    public static void main(String args[]) {
        Scanner scanner = new Scanner(System.in);
        String product = scanner.next();
        String city = scanner.next();
        int quantity = scanner.nextInt();

        double coffeePrice = 0.45;
        double waterPrice = 0.7;
        double beerPrice = 1.1;
        double sweetsPrice = 1.35;
        double peanutsPrice = 1.55;

        switch (city) {
            case "Sofia" : coffeePrice += 0.05;  waterPrice += 0.1; beerPrice += 0.1; sweetsPrice += 0.1; peanutsPrice +=0.05; break;
            case "Plovdiv" : coffeePrice -= 0.05; beerPrice += 0.05; sweetsPrice -= 0.05; peanutsPrice -= 0.05; break;
        }
        switch (product) {
            case "coffee" : System.out.printf("%.2f", coffeePrice * quantity); break;
            case "water" : System.out.printf("%.2f", waterPrice * quantity); break;
            case "beer" : System.out.printf("%.2f", beerPrice * quantity); break;
            case "sweets" : System.out.printf("%.2f", sweetsPrice * quantity); break;
            case "peanuts" : System.out.printf("%.2f", peanutsPrice * quantity); break;
        }
    }
}