Code:
Sub saveProgressiveNumber()
Dim fs, snum As String
Set fs = CreateObject("Scripting.FileSystemObject")
Fname = " Ivan Ivanov "
fpath = "your path"
If Dir(fpath & "*.xls*") = "" Then
  ThisWorkbook.SaveAs (fpath & Fname & "0001.xlsm")
Else
  Set f = fs.GetFolder(fpath)
  Set NFile = f.Files
  For Each pf1 In f.Files
    date3 = pf1.DateLastModified
    Fname1 = pf1.Name
    If MDataUM < date3 Then
      FpathName = pf1
      MDataUM = date3
      fnameExt = Fname1
    End If
  Next
  fnum = Val(Mid(FpathName, InStr(FpathName, "-") + 1, 4)) + 1
  snum = Format(fnum, "0000")
  ThisWorkbook.SaveAs (fpath & Fname & snum & ".xlsm")
End If
End Sub