Smart Lilli

using System;



class Program
{
    static void Main()
    {

        int N = int.Parse(Console.ReadLine());
        double woundryPrice = double.Parse(Console.ReadLine());
        int singleToyPrice = int.Parse(Console.ReadLine());
        int numberOfToys = 0;
        int presentInMoney = 0;
        int totalPresentsInMoney = 0;

        for (int i = 1; i <= N; i++)
        {
            if (i%2!=0)
            {
                numberOfToys += 1;
            }
            else if(i%2==0)
            {
                presentInMoney += 10;
                totalPresentsInMoney += presentInMoney-1;
            }
        }
        int MoneyFromToys = numberOfToys * singleToyPrice;

        double moneyCollected = MoneyFromToys + totalPresentsInMoney;

        if (moneyCollected>= woundryPrice)
        {
            Console.WriteLine("Yes! {0:f2}", moneyCollected-woundryPrice);
        }
        else
        {
            Console.WriteLine("No! {0:f2}", woundryPrice-moneyCollected);
        }
    }
}