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So the difficulty is how to identify buildings, with several floors as well and courtyards in-between the buildings.
I adjust your mappings and will show you the results.
The incorrect mappings of other mappers are modified as well.
Check this webpage
https://overpass-api.de/achavi/?changeset=165973999
If you hoover over the mapping, you see who mapped or adjusted it.
I suggest selecting another project with easier to map buildings till you gain more experience.
Best regards