How to create Google Analytics Custom filter to show only traffic from UK?

I created a new filter, defined it as 'Custom filter', but now what?? Which option do I have to use: 'Include' or 'Advanced', a开发者_如何学Cnd what is the syntax/pattern to UK only?

Thanks! Michelle.

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Include -> Filter Pattern -> United Kingdom

The syntax of how the country is listed should follow how the country is listed in the Map Overlay report.