The Seversky Donets (Russian: Се́верский Доне́ц) or Siverskyi Donets (Ukrainian: Сіверський Донець), usually simply called the Donets (Russian: Донец, lit. 'Don + - ets, suffix'), is a river on the south of the East European Plain. It originates in the Central Russian Upland, north of Belgorod, flows south-east through Ukraine (Kharkiv, Donetsk and Luhansk Oblasts) and then again through Russia (Rostov Oblast) to join the river Don, about 100 km (62 mi) from the Sea of Azov.
https://en.wikipedia.org/wiki/Donets