Complex sentence: He graduated the Ryazan State Medical University in 1963, from 1971 to 1973 crossed the Kamchatka and Chokotskaya tundras with dog-sledges, traveling as far as the North Sea.
Split into simpler sentences: He graduated the Ryazan State Medical University in 1963. From 1971 to 1973 he traversed the Kamchatka and Chokotskaya tundras on dog-sleds, traveling as far as the North Sea.