14. Factorial Trailing Zeroes

using System;

using System.Numerics;

namespace Factorial_Trailing_Zeroes
{
    class Program
    {
        static void Main(string[] args)
        {
            BigInteger numberInt = BigInteger.Parse(Console.ReadLine());
            BigInteger result = numberInt;

            for (BigInteger i = 1; i < numberInt; i++)
            {
                result = result * i;
            }
            Console.WriteLine(findTrailingZeros(numberInt) );

        }
        static BigInteger findTrailingZeros(BigInteger number)
        {
            BigInteger countZeroes = 0;
            for (BigInteger divider = 5; number / divider >= 1; divider *= 5)
            {
                countZeroes += number / divider;
            }
            return countZeroes;
        }
    }
}