Complex sentence: In 1922 he started working as a diplomat at various posts including London, Tokyo, and Helsinki, but in 1924, he also served as the first editor of the Petrograd literary magazine "Zvezda".
Split into simpler sentences: In 1922 he started working as a diplomat at various posts including London, Tokyo, and Helsinki. In 1924, he became the first editor of the Petrograd literary magazine "Zvezda".