Apex domains cannot have CNAME records.
Question and response
Question
dig imt.ru. NS
Answer
imt.ru. 5 NS ns.msu.net.
imt.ru. 5 NS ns.msu.ru.
Authority
The response has no authority records.
Additional
ns.msu.ru. 5 A 93.180.0.1
ns.msu.net. 5 A 212.16.0.1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0