using System;

public class Program

{

    public static void Main()

    {

        var start = 4;

        var max = 10;

        var min = 0;

        var stepSize = 1;

        int iUp = start + stepSize;

        int iDown = start - stepSize;

        Console.WriteLine(start);

        while (iUp <= max || iDown >= min)

        {

            if (iUp <= max)

            {

                Console.WriteLine(iUp);

                iUp += stepSize;

            }

            if (iDown >= min)

            {

                Console.WriteLine(iDown);

                iDown -= stepSize;

            }   

        }

    }

}