Macro Unir Archivos de Excel

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Sub UnirFiles() Dim Hoja As Object Application.DisplayAlerts = False A = ActiveWorkbook.Name R = ActiveWorkbook.Path ChDir R & "\" archi = Dir("*.xls*") Do While archi <> A Workbooks.Open archi B = ActiveWorkbook.Name For Each Hoja In ActiveWorkbook.Sheets Hoja.Copy After:=Workbooks(A).Sheets(Workbooks(A).Sheets.Count) Next Workbooks(B).Close False archi = Dir() Loop End Sub