Login to your account, and click on your username and icon in the top right corner. A drop down menu will appear. Now click the "Account settings" button. Go to the second option called "Location" and choose your country below. After you are done, click the button that says "Save my changes" and then your location will be saved.
Note: There used to be a bug that could allow users to change their location to any ISO 3116 Alpha-2 country code, which would allow for locations such as AT and ST, but it has since been removed.
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