spoj.pl Factorial final

using System;

namespace Factorial
{
    class MainClass
    {

        static int fivePowerSum (int x)
        {
            return (int)((Math.Pow (5, x) - 1) / 4);
        }

        static int z (int x)
        {
            if (x < 5)
                return 0;

            int result = 0;
            int log;

            do {

                log = -1;
                int fivePower = 1;
                do {
                    fivePower *= 5;
                    log++;
                } while (x>=fivePower);

                int fivePowerDiv5 = fivePower / 5;
                result += (fivePowerDiv5 - 1) / 4;
                x -= fivePowerDiv5;

            } while (log>0);

            return result;

        }

        public static void Main (string[] args)
        {
            int testCases = Convert.ToInt32 (Console.ReadLine ());
            int[] xs = new int[testCases];
            for (int i=0; i<testCases; i++)
                xs [i] = Convert.ToInt32 (Console.ReadLine ());
            foreach (int x in xs)
                Console.WriteLine (z (x));
        }
    }
}