below zero macro problem

[anon125]

this macro works
Sub goalSeekSample()
Dim seekValue As Double
Dim changeCell As Range
Inflation = Range("O7").Value
seekValue = InputBox("What's the value to seek?")
For Each changeCell In Range("N18:N32").Cells
changeCell.GoalSeek Goal:=seekValue, _
ChangingCell:=changeCell.Offset(0, -4)
seekValue = seekValue + (seekValue * Inflation)
Next changeCell
End Sub

but i don't want the ChangeCell to go below zero.
how do i amend this ? (without crashing of course!)
thanks

[Leith Ross]

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