@Pleuvoir, check out this thread:
https://polishforums.com/language/ethnic-backround-suffixes-surnames-72736/"Other typical suffixes of the Ukrainian group are
-uk,
-czuk (Andrzejuk, Antoniuk, Chilimoniuk, Filipiuk, Grygoruk, Jasiuk, Kononiuk, £ukaszuk, Pawluczuk, Pietruczuk)."
Makaruk, and Demetry Savchuk.
Definitely Ukrainian. There are Poles with surname "Makaruk" (probably with Ukrainian roots), but "Demetry" isn't a Polish name.