Simplify the following text for a Grade 10 native English-speaking person.
Original: He was President of Poland twice : first in December 1922 after the assassination of president Gabriel Narutowicz as Acting President of the Republic of Poland for one week , and again in May 1926 , after JÃ zef PiÅ sudski 's May Coup and the resignation of president StanisÅ aw Wojciechowski .
Simplified: He served as Acting President twice : from 16 December to 22 December 1922 and from 15 May to June 4 1926 . For the first time he served between assassination of Poland 's first President Gabriel Narutowicz and election of his successor StanisÅ aw Wojciechowski .