This CustomOST brings the melodies from the popular Russian cartoon series, Smeshariki, better known in the US as "Kikoriki" or "GoGoRiki". You might've heard of it. I dunno.
For those who DON'T know:
Kikoriki, known in the United States as GoGoRiki or BalloonToons and in Russia as Smeshariki (Russian: Смешарики), is a Russian animated television series consisting of 209 episodes of 6 minutes and 30 seconds each, aimed at children of 3 to 8 years. This series uses both flash animation and computer animation.