telerik carpets

using System;

class Carpets
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine()) / 2;
        string slash1 = "";
        string slash2 = "";
        string dots = new string('.', n);
        for (int i = 1; i <= n; i++)
        {
            if (i % 2 == 1)
            {
                slash1 = slash1 + "/";
                slash2 = "\\" + slash2;
            }
            else
            {
                slash1 = slash1 + " ";
                slash2 = " " + slash2;
            }

            dots = dots.Substring(1);
            Console.WriteLine(dots + slash1 + slash2 + dots);
        }

        if (n % 2 == 0)
        {
            slash1 = slash1.Substring(1) + slash1[0];
            slash2 = slash2.Substring(1) + slash2[0];
        }

        for (int i = n-1; i >= 0; i--)
        {
            Console.WriteLine(dots + slash2 + slash1 + dots);
            dots = dots + ".";
            slash2 = slash2.Remove(i);
            slash1 = slash1.Substring(1);
        }
    }
}