Imports System

Public Module Module1

    Public Sub Main()

        Console.WriteLine(GetFormattedString("F406697228D3"))

    End Sub

     Public Function GetFormattedString(input As String) As String

        Dim result As String = String.Empty

        For index = 0 To input.Length Step +2

            result += input.Substring(index, Math.Min(2, input.Length - index)) + "-"

        Next

        Return result.Trim("-")

    End Function

End Module