CleverLily

import java.util.Scanner;

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

        int age = Integer.parseInt(scanner.nextLine());
        double machinePrice = Double.parseDouble(scanner.nextLine());
        int toyPrice = Integer.parseInt(scanner.nextLine());
        double totalPrice = 0;
        int counter = 1;
        int toysCount = 0;

        for (int i = 1; i <= age; i++){
            if (i % 2 == 0){
               totalPrice += 10 * counter;
               counter++;
            }else{
                toysCount++;

            }
        }

        totalPrice -= counter - 1;
        int totalToysPrice = toyPrice * toysCount;
        totalPrice += totalToysPrice;

        if (totalPrice >= machinePrice){
            System.out.printf("Yes! %.2f", totalPrice - machinePrice);
        }else{
            System.out.printf("No! %.2f", machinePrice - totalPrice);

        }
    }
}