$1)$ ConferencesDemo

$2)$ My code is running fine, but I cannot get grade yet. This are my ERRORS:

Reason: Unable to run ConferencesDemo.cs

Unhandled Exception:

System.ArgumentNullException: Value cannot be null.

Parameter name: s

Please assist me$.$

using System;

using static System.Console;

using System.Globalization;

using System.Collections.Generic;

class Conference : IComparable

$\{$

public string Group $\{$ get; set; $\}$

public string Date $\{$ get; set; $\}$

public int Attendees $\{$ get; set; $\}//$ least to greatest attendees

public int CompareTo$($Conference other$)$

$\{$

return Attendees.CompareTo$($other$.$Attendees$)$;

$\}$

$\}$

$//$ NAME Conference starts on DATE and has ATTENDEES attendees

class ConferencesDemo $//$ Conference

$\{$

static void Main$()//$ static

$\{$

List conferences $=$ new List$()$;

for $($int i $=0$; i $<mtext\; id="EditorElement\_237709"></mtext><mn\; id="EditorElement\_237710">5</mn>$; i$++)//5$ times

$\{$

Conference conference $=$ new Conference$()$;

Write$("$Group: $")$;

conference.Group $=$ReadLine$()$;

Write$("$Date: $")$;

conference.Date $=$ ReadLine$()$;

Write$("$Attendees: $")$;

conference.Attendees $=$ int.Parse$($ReadLine$())$;

conferences.Add$($conference$)$;

$\}$

conferences.Sort$()$;

ReadLine$()$;

foreach $($var conference in conferences$)$

$\{$

WriteLine$($$$"\{$conference$.$Group$\}$ Conference starts on $\{$conference$.$Date$\}$ and has $\{$conference$.$Attendees$\}$ attendees"$)$;

$\}$

$\}$

$\}$