Private Sub Worksheet_Change(ByVal Target As Range)
Dim x As Integer
If Target.Address <> "$A$1" Then Exit Sub
If Not IsNumeric(Target.Value) Then Exit Sub
On Error GoTo ErLine
x = Int(Target.Value)
If x > 14 Or x < 1 Then Exit Sub
Columns(3).SpecialCells(xlCellTypeFormulas) _
.NumberFormat = "###." & String(x, "0")
ErLine:
End Sub