import java.util.Scanner;

public class SmallShop {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String product = scanner.nextLine();
        String town = scanner.nextLine();
        double quantity = Double.parseDouble(scanner.nextLine());
        double productPrice = 0;


        switch (town) {
            case "Sofia":
                if (product.equals("coffee")) {
                    productPrice = 0.5;
                } else if (product.equals("water")) {
                    productPrice = 0.8;
                } else if (product.equals("beer")) {
                    productPrice = 1.20;
                } else if (product.equals("sweets")) {
                    productPrice = 1.40;
                } else if (product.equals("peanuts")) {
                    productPrice = 1.60;
                }
                break;
            case "Plovdiv":
                if (product.equals("coffee")) {
                    productPrice = 0.4;
                } else if (product.equals("water")) {
                    productPrice = 0.7;
                } else if (product.equals("beer")) {
                    productPrice = 1.15;
                } else if (product.equals("sweets")) {
                    productPrice = 1.30;
                } else if (product.equals("peanuts")) {
                    productPrice = 1.50;
                }
                break;
            case "Varna":
                if (product.equals("coffee")) {
                    productPrice = 0.45;
                } else if (product.equals("water")) {
                    productPrice = 0.70;
                } else if (product.equals("beer")) {
                    productPrice = 1.10;
                } else if (product.equals("sweets")) {
                    productPrice = 1.35;
                } else if (product.equals("peanuts")) {
                    productPrice = 1.55;
                }
                break;
        }
            double totalPrice = productPrice*quantity;

            System.out.println(totalPrice);
    }
}