import java.util.Scanner;

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

        String day = scanner.nextLine();
        String fruit = scanner.nextLine();
        double quantity = Double.parseDouble(scanner.nextLine());
        double price = 0.0;

        if ("Monday".equals(day) ||
                "Tuesday".equals(day) ||
                "Wednesday".equals(day) ||
                "Thursday".equals(day) ||
                "Friday".equals(day)) {
            if ("banana".equals(fruit)) {
                price = 2.50;
            } else if ("apple".equals(fruit)) {
                price = 1.20;
            } else if ("orange".equals(fruit)) {
                price = 0.85;
            } else if ("grapefruit".equals(fruit)) {
                price = 1.45;
            } else if ("kiwi".equals(fruit)) {
                price = 2.70;
            } else if ("pineapple".equals(fruit)) {
                price = 5.50;
            } else if ("grapes".equals(fruit)) {
                price = 3.85;
            }
        }
        else if ("Saturday".equals(day) || "Sunday".equals(day)) {

            if ("banana".equals(fruit)) {
                price = 2.70;

            } else if ("apple".equals(fruit)) {
                price = 1.20;

            } else if ("orange".equals(fruit)) {
                price = 0.90;

            } else if ("grapefruit".equals(fruit)) {
                price = 1.60;

            } else if ("kiwi".equals(fruit)) {
                price = 3.00;

            } else if ("pineapple".equals(fruit)) {
                price = 5.60;

            } else if ("grapes".equals(fruit)) {
                price = 4.20;
            }
        }
        if (price > 0) {
            System.out.printf("%.2f", price * quantity);
        } else {
            System.out.println("error");
        }
    }

}