import java.util.Scanner;

public class app1 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String product = scanner.next();
        String grad = scanner.next();
        int broi = scanner.nextInt();
        double price = 0;

        if (product.equals("coffee")) {
            if (grad.equals("Sofia")) {
                price = 0.5 * broi;
                System.out.println(price);
            } else if (grad.equals("Plovdiv")) {
                price = 0.4 * broi;
                System.out.println(price);

            } else if (grad.equals("Varna")) {
                price = 0.45 * broi;
                System.out.println(price);
            }

        }

        if (product.equals("water")) {
            if (grad.equals("Sofia")) {
                price = 0.8 * broi;
                System.out.println(price);

            } else if (grad.equals("Plovdiv")) {
                price = 0.7 * broi;
                System.out.println(price);

            } else if (grad.equals("Varna")) {
                price = 0.7 * broi;
                System.out.println(price);
            }

        }
        if (product.equals("beer")) {
            if (grad.equals("Sofia")) {
                price = 1.20 * broi;
                System.out.println(price);

            } else if (grad.equals("Plovdiv")) {
                price = 1.15 * broi;
                System.out.println(price);

            } else if (grad.equals("Varna")) {
                price = 1.10 * broi;
                System.out.println(price);
            }
        }
        if (product.equals("sweets")) {
            if (grad.equals("Sofia")) {
                price = 1.45 * broi;
                System.out.println(price);

            } else if (grad.equals("Plovdiv")) {
                price = 1.30 * broi;
                System.out.println(price);

            } else if (grad.equals("Varna")) {
                price = 1.35 * broi;
                System.out.println(price);
            }
        }

        if (product.equals("peanuts")) {
            if (grad.equals("Sofia")) {
                price = 1.60 * broi;
                System.out.println(price);

            } else if (grad.equals("Plovdiv")) {
                price = 1.50 * broi;
                System.out.println(price);

            } else if (grad.equals("Varna")) {
                price = 1.55 * broi;
                System.out.println(price);
            }
        }
    }
}