BOSTON (AP) — A diary kept by a young John F. Kennedy during his brief stint as a journalist after World War II in which he reflected on Hitler, the ambitions of the Soviet Union and the weakness of the United Nations is up for auction. The diary was written in 1945 when the 28-year-old Kennedy was a correspondent for Hearst newspapers, rubbing shoulders with world leaders and traveling through a devastated Europe. Boston-based RR Auction says the diary is expected to fetch about $200,000 at auction April 26. The 61-page diary, mostly typed but including 12 handwritten pages, was given by Kennedy to Deirdre Henderson, a research assistant in his campaign office in the late 1950s. "What's remarkable is what he foresaw about the future of a world he would lead 16 years later," said Henderson, who lives in the Boston area. The experiences and reflections in the diary undoubtedly influenced Kennedy's presidency, auction house officials said. "This exceptional diary sheds light on a side of John F.