Complex sentence: It also borders Volgograd and Voronezh Oblasts in the north, Krasnodar and Stavropol Krais in the south, and the Republic of Kalmykia in the east.
Split into simpler sentences: It also borders Volgograd and Voronezh Oblasts in the north. Lastly, it borders Krasnodar and Stavropol Krais in the south, as well as the Republic of Kalmykia in the east.