Sub CheckRange()
Dim RngChk As String, Rng1 As String, Rng2 As String
Dim rMax As Long, rMin As Long, cMax As Long, cMin As Long, nTmp As Long
Dim vt1 As Long, vt2 As Long, ten As String, kytu As String
On Error Resume Next
Rng1 = Selection.SpecialCells(xlCellTypeConstants, 23).Address(, , xlR1C1)
Rng2 = Selection.SpecialCells(xlCellTypeFormulas, 23).Address(, , xlR1C1)
RngChk = Rng1 & "," & Rng2 & "Z"
rMin = Cells.Rows.Count
cMin = Cells.Columns.Count
vt1 = 1
Do
  ten = Mid(RngChk, vt1, 1)
  If ten = "R" Or ten = "C" Then
    vt1 = vt1 + 1
    vt2 = vt1
    Do
      kytu = Mid(RngChk, vt2, 1)
      If IsNumeric(kytu) = False Then
'        Stop
        nTmp = Mid(RngChk, vt1, vt2 - vt1)
        If nTmp > rMax And ten = "R" Then rMax = nTmp
        If nTmp < rMin And ten = "R" Then rMin = nTmp
        If nTmp > cMax And ten = "C" Then cMax = nTmp
        If nTmp < cMin And ten = "C" Then cMin = nTmp
        vt1 = vt2
        Exit Do
      Else
        vt2 = vt2 + 1
      End If
    Loop
  Else
    vt1 = vt1 + 1
  End If
Loop While vt1 < Len(RngChk)
MsgBox "rMin=" & rMin & " rMax=" & rMax & "    cMin=" & cMin & "   cMax=" & cMax
End Sub