Among the patients followed at the outpatient clinic, how many of them have a normal level of alkaliphophatase?
followed at the outpatient clinic refers to Admission = '-'; normal level of alkaliphophatase refers to ALP < 300;
SELECT COUNT(T1.ID) FROM Patient AS T1 INNER JOIN Laboratory AS T2 ON T1.ID = T2.ID WHERE T2.ALP < 300 AND T1.Admission = '-'