Exam 3. Bit Sifting

namespace _5.BitSifting_Bitwise
{
    using System;

    public class BitSifting
    {
        public static void Main(string[] args)
        {
            checked
            {
                ulong initialBits = ulong.Parse(Console.ReadLine());
                int countSieves = int.Parse(Console.ReadLine());

                for (int i = 0; i < countSieves; i++)
                {
                    ulong sieve = ulong.Parse(Console.ReadLine());
                    initialBits = (initialBits ^ sieve) & initialBits;
                }

                // Console.WriteLine("Result num: " + initialBits);
                // Console.WriteLine("In Binary string: " + Convert.ToString((long)initialBits, 2));
                int bitCounter = 0;
                for (int bit = 0; bit < 64; bit++)
                {
                    if ((initialBits & 1) > 0)
                    {
                        bitCounter++;
                    }

                    initialBits >>= 1;
                }

                Console.WriteLine(bitCounter);
            }
        }
    }
}