Easter Party

using System;

namespace EasterParty
{
    class Program
    {
        static void Main(string[] args)
        {
            int guest = int.Parse(Console.ReadLine());
            double envelope = double.Parse(Console.ReadLine());
            double budget = double.Parse(Console.ReadLine());

            double sum = guest * envelope;

            if (guest >= 10 && guest <=15)
            {
                sum *= 0.85;
            }
            else if (guest > 15 && guest <= 20)
            {
                sum *= 0.8;
            }
            else if (guest > 20)
            {
                sum *= 0.75;
            }
            sum += budget / 10;

            if (budget >= sum)
            {
                Console.WriteLine($"It is party time! {budget - sum:F2} leva left.");
            }
            else
            {
                Console.WriteLine($"No party! {sum - budget:F2} leva needed.");
            }
        }
    }
}