SmartLili

import java.util.Scanner;

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

        int age = Integer.parseInt(scanner.nextLine());
        double machinePrice = Double.parseDouble(scanner.nextLine());
        double toysPrice = Double.parseDouble(scanner.nextLine());
        double result1 = 0;
        double result2 = 0;
        double result3 = 0;
        double totalResult = 0;
        double end = 0;
        int num=0;
        int num2 =0 ;

        for (int i = 1; i <=age; i++) {
            if (i%2==0){
                    num += 10;
                    result1 += num;
                    num2 +=1;
                    result2 = result1 - num2;
            } else {
                result3 +=toysPrice;
            }
        }
        totalResult = result2 + result3;
        end = (totalResult - machinePrice);
        if (totalResult>=machinePrice){
            System.out.printf("Yes! %.2f", Math.abs(end));
        } else {
            System.out.printf("No! %.2f", Math.abs(end));
        }
    }
}