import java.util.Scanner;



public class Main
{
	public static void main(String[] args) {
	    Scanner scan = new Scanner(System.in);
	    String dring = scan.nextLine();
	    String city = scan.nextLine();
	    int num = Integer.parseInt(scan.nextLine());
	   double money = 0;
	    if (city.equals("Sofia")){
	        if (dring.equals("coffe")){
	            money = 0.5 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("water")){
	            money = 0.8 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("beer")){
	            money = 1.2 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("sweets")){
	            money = 1.45 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("peanuts")){
	            money = 1.6 * num;
	            System.out.println(money);
	        }
	    }
	     else if (city.equals("Plovdiv")){
	        if (dring.equals("coffe")){
	            money = 0.4 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("water")){
	            money = 0.7 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("beer")){
	            money = 1.15 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("sweets")){
	            money = 1.3 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("peanuts")){
	            money = 1.5 * num;
	            System.out.println(money);
	        }
	    }
	    else if (city.equals("Varna")){
	        if (dring.equals("coffe")){
	            money = 0.45 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("water")){
	            money = 0.7 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("beer")){
	            money = 1.1 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("sweets")){
	            money = 1.35 * num;
	            System.out.println(money);
	        }
	        else if  (dring.equals("peanuts")){
	            money = 1.55 * num;
	            System.out.println(money);
	        }
	    }
	}
}