Complex sentence: He is one three Finnish presidents whose portraits have appeared on markka-denominated banknotes of Finland, along with Kaarlo Juho Ståhlberg, the first president of Finland, and Urho Kekkonen, Paasikivi's successor as president.
Split into simpler sentences: He is one three Finnish presidents whose portrait has appeared on markka-denominated banknotes of Finland. The others were Kaarlo Juho Ståhlberg, the first president of Finland; and Urho Kekkonen, Paasikivi's successor as president.