Sum of smaller elements of nodes in a linked list in vb.net

Vb program for Sum of smaller elements of nodes in a linked list. Here problem description and other solutions.

' Include namespace system
Imports System 
' Vb.net program for
' Sum of smallest element of linked list

'  Linked list node
Public Class LinkNode
    Public  a As Integer
    Public  b As Integer
    Public  [next] As LinkNode
    Public Sub New(ByVal a As Integer, 
                   ByVal b As Integer)
        Me.a = a
        Me.b = b
        Me.next = Nothing
    End Sub
End Class
public Class SingleLL
    Public  head As LinkNode
    Public  tail As LinkNode
    Public Sub New()
        Me.head = Nothing
        Me.tail = Nothing
    End Sub
    Public Sub insert(ByVal a As Integer, 
                      ByVal b As Integer)
        Dim node As LinkNode = New LinkNode(a, b)
        if (Me.head  Is  Nothing) Then
            '  Add first node
            Me.head = node
        Else
            '  Add node at the end position
            Me.tail.[next] = node
        End IF
        '  new last node
        Me.tail = node
    End Sub
    '  Display linked list element
    Public Sub display()
        if (Me.head  Is  Nothing) Then
            Return
        End If
        Dim temp As LinkNode = Me.head
        '  iterating linked list elements
        while (temp IsNot Nothing)
            Console.Write(" (" + temp.a.ToString() + 
                          "," + temp.b.ToString() + ") →")
            '  Visit to next node
            temp = temp.[next]
        End While
        Console.WriteLine(" NULL")
    End Sub
    '  Find the sum of smaller elements of 
    '  every node in a linked list
    Public Function  nodeSum() As Integer
        Dim result As Integer = 0
        Dim temp As LinkNode = Me.head
        if (temp  Is  Nothing) Then
            Console.WriteLine("Empty linked list")
        Else
            '  Iterate the linked list
            '  And 
            '  Sum of smallest key in every node of linked list
            while (temp IsNot Nothing)
                if (temp.a > temp.b) Then
                    '  When key b is small      
                    result += temp.b
                Else
                    '  When key a is small     
                    result += temp.a
                End IF
                '  Visit to next node
                temp = temp.[next]
            End While
        End IF
        Return  result
    End Function
    Public Shared Sub Main(ByVal args As String())
        Dim sll As SingleLL = New SingleLL()
        '  Add pair
        '  (3,9) → (11,4) → (3,3) → (6,1) → (2,9) → (4,7) → NULL
        sll.insert(3, 9)
        sll.insert(11, 4)
        sll.insert(3, 3)
        sll.insert(6, 1)
        sll.insert(2, 9)
        sll.insert(4, 7)
        Console.WriteLine(" Linked List")
        sll.display()
        Console.WriteLine(" Result : " + sll.nodeSum().ToString())
    End Sub
End Class

Output

 Linked List
 (3,9) → (11,4) → (3,3) → (6,1) → (2,9) → (4,7) → NULL
 Result : 17