spoj.pl Factorial

using System;

namespace Factorial
{
    class MainClass
    {

        static int z (int x)
        {
            int result = 0;
            int[] fivePowerModulo = new int[ (int)Math.Log (x, 5) + 1];
            for (int i=1; i<=x; i++) {

                int j = 0;

                Power:
                fivePowerModulo [j]++;
                if (fivePowerModulo [j] == 5) {
                    fivePowerModulo [j] = 0;
                    j++;
                    goto Power;
                }

                result += j;

            }
            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));
        }
    }
}