How many donors in Los Angeles donated to school in another city?
in Los Angeles refers to donor_city = 'Los Angeles'; school in another city refers to school_city ! = 'Los Angeles'
SELECT COUNT(T2.schoolid) FROM donations AS T1 INNER JOIN projects AS T2 ON T1.projectid = T2.projectid WHERE T1.donor_city = 'Los Angeles' AND T2.school_city NOT LIKE 'Los Angeles'