Моля за помощ

Това ми е решението, а Judge не го приема. Получавам грешка:

Unhandled Exception: System.FormatException: String was not recognized as a valid DateTime.
   at System.DateTimeParse.Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles)
   at _05.Date_after_5_Days.Program.Main(String[] args)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _05.Date_after_5_Days
{
    class Program
    {
        static void Main(string[] args)
        {
            int date = int.Parse(Console.ReadLine());
            int month = int.Parse(Console.ReadLine());
            string dateMonth = "" + date + "."+month;
            var newDate = DateTime.Parse(dateMonth);
            newDate = newDate.AddDays(5);
            Console.WriteLine($"{newDate:d.MM}");
          //  Console.WriteLine(newDate.ToString("d/MM"));
        }
    }
}