Concatenate formula

[Jokacave]

Hi,
I try change code numbers like the follow one
0101010100
in this
01-01-01-01-00
and I know that with this formula

=(CONCATENATE(LEFT(A2;2);"-";MID(A2;3;2);"-";MID(A2;5;2);"-";MID(A2;7;2);"-";RIGHT(A2;2)))

I can work it out.
So I create the following code

Dim R As Long
R = 2
    Do Until Trim(Cells(R, 1)) = ""
        If Len(Cells(R, 1)) = 10 Then
        Cells(R, 1).Offset(0, 2).Formula = "=(CONCATENATE(LEFT(A" & R & ";2);""-"";MID(A" & R & ";3;2);""-"";MID(A" & R & ";5;2);""-"";MID(A" & R & ";7;2);""-"";RIGHT(A" & R & ";2)))"
        ElseIf Len(Cells(R, 1)) = 8 Then
        Cells(R, 1).Offset(0, 2).Formula = "=(CONCATENATE(LEFT(A" & R & ";2);""-"";MID(A" & R & ";3;2);""-"";MID(A" & R & ";5;2);""-"";RIGHT(A" & R & ";2)))"
        Else
        Cells(R, 1).Offset(0, 2).Value = "TTTTTT"
    End If
    R = R + 1
    Loop

but doenst work.
Can somebody help me.
Thanks in advance