Context: The first half of the 20th century in Russia and the Soviet Union was marked by a succession of wars, famines and other disasters, each accompanied by large-scale population losses. Stephen J. Lee estimates that, by the end of World War II in 1945, the Russian population was about 90 million fewer than it could have been otherwise.

Question: The first half of the 20th century was marked by what in Russia and the Soviet Union?
Answer: succession of wars, famines and other disasters

Question: Who estimated the Russian population was 90 million fewer than it could have been in 1945?
Answer: Stephen J. Lee

Question: When was the Russian population estimated to be about 90 million fewer than it could have been?
Answer: 1945

Question: What was marked by succession of wars, famines, and other disasters in the 20th century?
Answer: Russia and the Soviet Union

Question: When did Stephen J. Lee make his estimate about the Russian population?
Answer: Unanswerable

Question: How many people did famine kill in Russia?
Answer: Unanswerable

Question: Who did Russia fight with in the first half of the 20th century?
Answer: Unanswerable

Question: Who ended the war in 1945?
Answer: Unanswerable

Question: What is Stephen J. Lee's nationality?
Answer: Unanswerable