Complex sentence: Flanagan graduated from Manchester (NH) Memorial High School, where he was on baseball and basketball teams that each won consecutive New Hampshire Interscholastic Athletic Association (NHIAA) Class L titles in 1970 and 1971.
Split into simpler sentences: Flanagan graduated from Manchester (NH) Memorial High School, where he excelled in baseball and basketball. He helped lead Memorial to consecutive New Hampshire Interscholastic Athletic Association (NHIAA) Class L titles in both sports in 1970 and 1971.