import com.sun.source.tree.WhileLoopTree;

import java.util.Scanner;

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

        String product = sc.nextLine();
        String town = sc.nextLine();
        double quantity = Double.parseDouble(sc.nextLine());
        double price = 0.0;

        if (town.equals("Sofia")) {

            switch (product) {
                case "coffee":
                    price = 0.50;
                    break;
                case "water":
                    price = 0.80;
                    break;
                case "beer":
                    price = 1.20;
                    break;
                case "sweets":
                    price = 1.45;
                    break;
                case "peanuts":
                    price = 1.60;
                    break;
                default:
                    break;
            }
        }
        if (town.equals("Plovdiv")) {

            switch (product) {
                case "coffee":
                    price = 0.40;
                    break;
                case "water":
                    price = 0.70;
                    break;
                case "beer":
                    price = 1.15;
                    break;
                case "sweets":
                    price = 1.30;
                    break;
                case "peanuts":
                    price = 1.50;
                    break;
                default:
                    break;

            }
        }
        if (town.equals("Varna")) {

            switch (product) {
                case "coffee":
                    price = 0.45;
                    break;
                case "water":
                    price = 0.70;
                    break;
                case "beer":
                    price = 1.10;
                    break;
                case "sweets":
                    price = 1.35;
                    break;
                case "peanuts":
                    price = 1.55;
                    break;
                default:
                    break;

            }
        }

        System.out.println(quantity * price);
    }
}