.NET Getting some ListBox items

Code
Dim attlist As New List(Of List(Of DateTime))

        For i = 0 To 30

            attlist.Add(New List(Of DateTime))



        Next

        For Each t As String In ListBox1.Items

            For i = 1 To 31

                If Convert.ToDateTime(t.Split(" "c)(0)).Month = i Then

                    attlist(i - 1).Add(t.Split(" "c)(0) & " " & t.Split(" "c)(t.Split(" "c).Length - 1))



                End If

            Next

        Next

        Dim p As Integer

        For i = 0 To 30

            If attlist(i).Count >= 2 Then

               



                Dim checkin, checkout As String



                checkin = ListBox1.Items(attlist(i).IndexOf(min(attlist(i))) + p)

                checkout = ListBox1.Items(attlist(i).IndexOf(max(attlist(i))) + p)

                Dim timestart, timeend As String

                timestart = checkin.Substring(checkin.LastIndexOf(" "))

                timeend = checkout.Substring(checkin.LastIndexOf(" "))

                Dim ENDTIME As Date

                Dim STARTTIME As Date

                STARTTIME = timestart

                ENDTIME = timeend

                Dim TOTALTIME As TimeSpan

                TOTALTIME = TimeSerial(Hour(ENDTIME), Minute(ENDTIME), Second(ENDTIME)) - TimeSerial(Hour(STARTTIME), Minute(STARTTIME), Second(STARTTIME))

                ListBox2.Items.Add("On date " & ListBox1.Items(attlist(i).IndexOf(max(attlist(i))) + p).Split(" "c)(0) & " worked " & TOTALTIME.ToString("hh") & " hour e " + TOTALTIME.ToString("mm") & " minutes")







                p += attlist(i).Count

            End If

        Next