using System;

class SmartLilly
{
    static void Main()
    {
        int age = int.Parse(Console.ReadLine());
        decimal washingPrice = decimal.Parse(Console.ReadLine());
        int toyPrice = int.Parse(Console.ReadLine());
        int toys = 0;
        int money = 0;
        int m = 0;
        int n = 0;
        decimal totalMoney = 0;
        decimal change = 0;
        for (int i = 1; i <= age; i++)
        {
            if (i % 2 == 0)
            {
                m += 10;
                money = money + m;
                n++;
            }
            else
            {
                toys++;
            }
        }
        totalMoney = (toys * toyPrice) + (money - n);
        if (washingPrice <= totalMoney)
        {
            change = totalMoney - washingPrice;
            Console.WriteLine("Yes! {0:F2}", change);
        }
        else
        {
            change = washingPrice - totalMoney;
            Console.WriteLine("No! {0:F2}", change);
        }
    }
}