Russian people received their last names (surnames) 100 years ago. It was during the first population census in 1897. Till this time last name was widespread in villages as nicknames. Then during the population census last names (surnames) was given after father's names. For example, if father's name was Peter, then the last name (surname) was Petrov (it is form of word Peter which is answer the question "whose you are?"). That is why the most widespread Russian last names: Ivanov, Petrov, Vasiliev, Nikitin, Tarasov, Titov, Fedoseev, Fedorov, Sidorov, Alekseev, Egorov, Demidov, Mihailov, Andreev, Alexandrov.
This would yield the Russian surname Klementov or Clementov, depending on the transliteration.