Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
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Question: The Church of the Savior on Spilled Blood, built on the site of the assassination of Tsar Alexander II, is in which Russian city?

Answer: church of the savior on blood


Question: Which alliteratively-named politician served as Abraham Lincoln's Vice-President between 1861 and 1865?

Answer: abraham lincoln


Question: Which TV cartoon series(later a film) features the children Pebbles and Bam Bam?

Answer:
pebbles flintstone