public class MyClass {
    public static void main(String args[]) {
        java.util.Scanner scanner = new java.util.Scanner(System.in);
        String city = scanner.nextLine();
        double commission = Double.parseDouble(scanner.next());
        double reduction = 500.0;
        boolean isCityValid = true;
        if (commission >= 0 && commission <= 500) {
            switch (city) {
                case "Sofia" : reduction = 0.05; break;
                case "Varna" : reduction = 0.045; break;
                case "Plovdiv" : reduction = 0.055; break;
                default : reduction = reduction;isCityValid = false;
            }
        }
        if (commission > 500 && commission <= 1000) {
            switch (city) {
                case "Sofia" : reduction = 0.07;break;
                case "Varna" : reduction = 0.075;break;
                case "Plovdiv" : reduction = 0.08;break;
                default : reduction = reduction;isCityValid = false;
            }
        }
        if (commission > 1000 && commission <= 10000) {
            switch (city) {
                case "Sofia" : reduction = 0.08; break;
                case "Varna" : reduction = 0.1;break;
                case "Plovdiv" : reduction = 0.12;break;
                default : reduction = reduction;isCityValid = false;
            }
        }
        if (commission > 10000) {
            switch (city) {
                case "Sofia" : reduction = 0.12;break;
                case "Varna" : reduction = 0.13;break;
                case "Plovdiv" : reduction = 0.145;break;
                default : reduction = reduction;isCityValid = false;
            }
        }
        if (reduction == 500 || !isCityValid) {
            System.out.print("error");
        } else {
            System.out.printf("%.2f", commission * reduction);
        }
    }
}