Fixed

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace beats
{
    class Program
    {
        static void Main(string[] args)
        {
            var guests = double.Parse(Console.ReadLine());
            var budget = double.Parse(Console.ReadLine());


            var priceforKuvert = guests * 20;
            var lastMoney = budget - priceforKuvert;
            var moneyforFoeverki = lastMoney * 0.4;
            var moneyForKids = lastMoney - moneyforFoeverki;


            if (priceforKuvert < budget)
            {
                Console.WriteLine($"Yes! {Math.Round(moneyforFoeverki)} lv are for fireworks and {Math.Round(moneyForKids)} lv are for donation." );
            }

            if (priceforKuvert > budget)
            {
                var all = priceforKuvert - budget;
                Console.WriteLine($"They won't have enough money to pay the covert. They will need {Math.Round(all)} lv more.");
            }
        }
    }
}