using System;

namespace zadachi
{
    class Program
    {
        static void Main(string[] args)
        {

            int age = int.Parse(Console.ReadLine());
            double washingmashine = double.Parse(Console.ReadLine());
            double toyPrice = double.Parse(Console.ReadLine());
            double savedMoney = 0;
            int toyCount = 0;
            double moneyByToys = 0;
            int moneyByBrother = 0;

            for (int i = 1; i <= age; i++)
            {
                if (i % 2 == 0)
                {
                    savedMoney += i * 5;
                    moneyByBrother++;
                }
                else
                {
                    toyCount++;
                    moneyByToys = toyCount * toyPrice;
                }
            }
            double totalMoney = (savedMoney - moneyByBrother) + moneyByToys;
            if (totalMoney >= washingmashine)
            {
                Console.WriteLine($"Yes! {totalMoney - washingmashine:f2}");
            }
            else
            {
                Console.WriteLine($"No! {washingmashine - totalMoney:f2}");
            }

        }
    }
}