How many donors have endowment for school named "Glenn"?
SELECT count(DISTINCT T1.donator_name) FROM endowment AS T1 JOIN school AS T2 ON T1.school_id  =  T2.school_id WHERE T2.school_name  =  "Glenn"
SELECT count(DISTINCT T1.donator_name) FROM endowment AS T1 JOIN school AS T2 ON T1.school_id  =  T2.school_id WHERE T2.school_name  =  "Glenn"
[{'count(DISTINCT T1.donator_name)': 3}]