Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
Application.EnableEvents = False
If Not Intersect(Target, Range("E3")) Is Nothing Then
Range("E5") = ""
End If
If Not Intersect(Target, Range("E5")) Is Nothing Then
If Range("E3") = "" Then Range("E5") = ""
End If
Application.EnableEvents = True
End Sub