Ukraine IS Russia. Russian Federation doesn't contain a region named «Russia».

Russia formed when Oleg from Novgorod killed Ascold and Dir (rulers of Kyїv) in 852AD, captured Kyїv, then called it as «mother of (new) Russian cities».

When Moscow tsar Petro I captured original Russia (now Ukraine), he appended «tsar of all Russia» to his tittle. Then Catherine II renamed Moscow kingdom to Russian Empire.

So, in short, RF is Russian, not Russia.