using System;

public class Program

{

    public static void Main()

    {

        // Case 1

        // var localDeadline = new DateTime(2017,7,6,   12,00,00) // 06-Jul - < LocalNow time

        // var localDeadline = new DateTime(2016,7,6,   20,00,00) // 06-Jul - > LocalNow time

        // Case 2

        // var localDeadline = new DateTime(2017,7,4,   20,00,00) // 04-Jul - > LocalNow time

        // var localDeadline = new DateTime(2016,7,4,   12,00,00) // 04-Jul - < LocalNow time

        // Case 3

        // var localDeadline = new DateTime(2015,7,5,   20,00,00) // 05-Jul - > LocalNow time

        // var localDeadline = new DateTime(2017,7,5,   20,00,00) // 05-Jul - <> LocalNow time

        // Case 4

        // var localDeadline = new DateTime(2016,7,5,   12,00,00) // 12:00 - < LocalNow time

        // var localDeadline = new DateTime(2017,7,6,   12,00,00) // 12:00 - < LocalNow time

        var localDeadline = new DateTime(2016,7,5,   12,00,00);

        var localNow = new DateTime(2016,7,5,   18,00,00);

        string result;        

                var timeToDeadline = (localDeadline - localNow).Duration();

                if (timeToDeadline < TimeSpan.FromHours(24))

                    result = localDeadline.ToString("HH:mm");

                else if (timeToDeadline < TimeSpan.FromDays(365))

                    result = localDeadline.ToString("dd-MMM");

                else

                    result = localDeadline.Year.ToString();

        var x = new DateTime(2017,2,29,   18,00,00);

        Console.WriteLine(result);

    }

}