Apex domains cannot have CNAME records.
Question and response
Question
dig vladivostok.RU. NS
Answer
vladivostok.ru. 4 NS ns.vlc.ru.
vladivostok.ru. 4 NS ns2.vlc.ru.
Authority
The response has no authority records.
Additional
ns.vlc.RU. 4 A 37.200.76.140
ns2.vlc.RU. 4 A 37.200.76.140
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0