Fibonacci VB.NET iterative

Function GetNthFibonacciNumber(ByVal n As Integer) As Integer
    Dim NextLast As Integer, Last As Integer, This As Integer
    If n = 0 Then
        Return 0
    ElseIf n = 1 Then
        Return 1
    Else
        NextLast = 0 : Last = 1
        For i As Integer = 2 To n
            This = NextLast + Last
            NextLast = Last
            Last = This
        Next i
        Return This
    End If
End Function