Complex sentence: Néstor Guillén Olmos (1890-1966) was President of Bolivia for 27 days between July and August 1946, following the overthrow and assassination of President Gualberto Villarroel (1943-46).
Split into simpler sentences: Néstor Guillén Olmos (1890-1966) was briefly President of Bolivia. He served as President of Bolivia for 27 days between July and August 1946, following the overthrow and assassination of President Gualberto Villarroel (1943-46).