using System;

public class Program

{

    public static void Main()

    {

        string input = "01182021";

        var result = IsResponseDateValid(input);

        Console.WriteLine(result.ToString());

    }

    public static Boolean IsResponseDateValid(string input)

    {

        DateTime outDate1;

        DateTime outDate2;

        string yearFirst = input.Substring(0, 4) + "-" + input.Substring(4, 2) + "-" + input.Substring(6, 2);

        Console.WriteLine(yearFirst);

        string yearLast =  input.Substring(0, 2) + "-" + input.Substring(2, 2) + "-" + input.Substring(4, 4) ;

        Console.WriteLine(yearLast);

        var success1 = DateTime.TryParse(yearFirst, out outDate1);

        var success2 = DateTime.TryParse(yearLast, out outDate2);

        if (outDate1 != DateTime.MinValue || outDate2 != DateTime.MinValue)

        {

            return true;

        }

        else return false;

    }

}