Hello Dawid. I'd refrain from making such statements as it depends with whom you talk to. ;) Believe me, until I found it myself, I did not understand why some Polish people call this city Roztoka. I thought they were joking or exaggerating, but yes, it exists! The name Roztoka does exist, and it is the Polish historical name for Rostock. Remember that this part of Germany was Slavic at first and lots of names have Slavic roots ;) Even Berlin is not a Germanic name, just like "Okmiany" or "Degucie" are not Slavic names ;)
http://maps.mapywig.org/m/WIG_maps/series/M1/MPIKO_1M_Arkusz_NW_WARSZAWA-POZNAN-GDYNIA_1943.jpg 
