Flying Days

	A	B	C
1	Inp	Out
2	123	123----	B2: =FlyingDays(A2)
3	345	--345--
4	x7	123456-
5	x15	-234-67
6	1234567	1234567
7	x	1234567

Function FlyingDays(sInp As String) As String
    Dim i           As Long

    If sInp Like Replace(Space(Len(sInp)), " ", "[1-7]") Then
        FlyingDays = "-------"
        For i = 1 To Len(sInp)
            Mid(FlyingDays, Mid(sInp, i, 1)) = Mid(sInp, i, 1)
        Next i

    ElseIf UCase(sInp) Like "X" & Replace(Space(Len(sInp) - 1), " ", "[1-7]") Then
        FlyingDays = "1234567"
        For i = 2 To Len(sInp)
            Mid(FlyingDays, Mid(sInp, i, 1)) = "-"
        Next i

    Else
        FlyingDays = "Invalid input!"
    End If
End Function