Beer stocks

using System;
using System.Text.RegularExpressions;

namespace beerstoc
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            ulong ReservedBeers = ulong.Parse(Console.ReadLine ());
            ulong Beers = 0, SixPacks = 0, Cases = 0;
            var Input = Console.ReadLine ().Split(' ');
            while (Input[0] != "Exam") {
                switch (Input[1]) {
                case "beers":
                    Beers += ulong.Parse(Input [0]);
                    Input = Console.ReadLine ().Split(' ');
                    break;
                case "sixpacks":
                    SixPacks += ulong.Parse(Input [0]);
                    Input = Console.ReadLine ().Split(' ');
                    break;
                case "cases":
                    Cases += ulong.Parse(Input [0]);
                    Input = Console.ReadLine ().Split(' ');
                    break;
                default:
                    Input = Console.ReadLine ().Split(' ');
                    break;
                }
            }
            ulong AvailableBeers = (Beers + SixPacks *6 +Cases*24) - (Beers + SixPacks *6 +Cases*24) / 100;
            if ((AvailableBeers)<ReservedBeers) {
                ulong NeededBeer = ReservedBeers - AvailableBeers;
//              if (NeededBeer >=100) {
//                  NeededBeer+=NeededBeer/100;
//              }
                Console.WriteLine ("Not enough beer. " +
                    "Beer needed: {0} cases" +
                    ", {1} sixpacks " +
                    "and {2} beers.",NeededBeer/24,(NeededBeer%24)/6,((NeededBeer%24)%6));
            } else {
                if (Beers>=ReservedBeers) {
                    Beers -= ReservedBeers;
                } else if ((SixPacks*6+Beers)>=ReservedBeers) {
                    ReservedBeers -= Beers;
                    SixPacks -= (ReservedBeers/6 - 1);
                    Beers = ReservedBeers % 6;
                } else {
                    ReservedBeers -= (Beers + SixPacks * 6);
                    Cases -= (ReservedBeers / 24 - 1);
                    if (SixPacks>=(ReservedBeers%24)/6) {
                        SixPacks = (ReservedBeers % 24) / 6;
                        Beers = ((ReservedBeers % 24) % 6);
                    } else {
                        SixPacks = 0;
                        Beers = ReservedBeers % 24;
                    }
                }
                Console.WriteLine ("Cheers! Beer left: {0} cases, {1} sixpacks and {2} beers.",Cases,SixPacks,Beers);
            }
        }
    }
}