using System;

namespace _02._Easter_Party
{
    class Program
    {
        static void Main(string[] args)
        {
            int guestNumber = int.Parse(Console.ReadLine());
            double pricePerGuest = double.Parse(Console.ReadLine());
            double budget = double.Parse(Console.ReadLine());
            double cakePrice = budget * 0.1;

            if (10 <= guestNumber && guestNumber <= 15)
            {
                pricePerGuest *= 0.85;
            }
            else if (15 <= guestNumber && guestNumber <= 20)
            {
                pricePerGuest *= 0.8;
            }
            else if (20 < guestNumber)
            {
                pricePerGuest *= 0.75;
            }
            double moneyNeededOrLeft = budget - ((guestNumber * pricePerGuest) + cakePrice);
            if (0 <= moneyNeededOrLeft)
            {
                Console.WriteLine($"It is party time! {moneyNeededOrLeft:f2} leva left.");
            }
            else
            {
                Console.WriteLine($"No party! {Math.Abs(moneyNeededOrLeft):f2} leva needed.");
            }
        }
    }
}