I downloaded JOSM and would be a trail from London (uk) to Lofoten (Norway) onto a map. But when I pick the card comes a popup window informing that the download area is too large. But where / how do I get a short covering Scandinavia?

I downloaded JOSM and would be a trail from London (uk) to Lofoten (Norway) onto a map. But when I pick the card comes a popup window informing that the download area is too large. But where / how do I get a short covering Scandinavia?