Sub es()
Dim i As Long, x, y
Application.ScreenUpdating = 0
For i = 2 To Cells(Rows.Count, 3).End(3).Row + 1
If Cells(i, 2) <> "" Then Cells(i, 5) = Cells(i, 2): x = Cells(i, 2)
If Cells(i, 2) = "" And Cells(i, 3) <> "" Then Cells(i, 5) = x & Cells(i, 3): y = Cells(i, 3)
If Cells(i, 2) = "" And Cells(i, 3) = "" And Cells(i, 4) <> "" Then Cells(i, 5) = x & y & Cells(i, 4)
Next i
End Sub