Set Panel2 width to 1px less than Panel1 width

Hi,
I have 2 panels.
What I am trying to do is to set the Panel8:s width to "1px" less thatn the Panels7: width.
The code compiles but the width does not get correct? Thanks!
Panel2.Attributes.Add("style", "width:" + Unit.Parse((Panel1.Width.Value - 1).ToString() + "px"));
 
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