how do i get recipient.count as value to add to if statement to change color on outlook calendar in vba?

I'm trying to get this code I found online that I modified to get my recipients.count value so I can add it into a if statement that will determine if there is one, two declines and change the calendar to a specific color based on the recipients declined count. I get the Compile Error: Can't assign to read-only property. If you can provide some help with this issue as I'm new to vba scripting and would like to get this to work. I'm using windows 10 with outlook 2016.

    Sub CheckDeclines(oRequest As MeetingItem)
    ' only check declines
     If oRequest.MessageClass <> "IPM.Schedule.Meeting.Resp.Neg" Then
      Exit Sub
    End If

    Dim oAppt As AppointmentItem
    Set oAppt = oRequest.GetAssociatedAppointment(True)
    Dim myAttendees As Integer
    Dim objAttendees As Outlook.recipients
    Set objAttendees = oAppt.recipients

   For x = 1 To objAttendees.Count
       If objAttendees(x).Type = olRequired Then
         oAppt.Categories = "Declined;"
         objAttendees.Count = myAttendees
       End If
   Next

    If myAttendees = 1 Then
    oAppt.Categories = "Declined;"
    oAppt.Categories = "Yellow Category"
    Else
    If myAttendees = 2 Then
    oAppt.Categories = "Declined;"
    oAppt.Categories = "Orange Category"
    Else
    oAppt.Categories = "Declined;"
    oAppt.Categories = "Red Category"
    End If
    End If

    oAppt.Display

    End Sub