How many allergies does Mrs. Saundra Monahan have?
allergies refer to PATIENT from allergies;
SELECT COUNT(DISTINCT T2.code) FROM patients AS T1 INNER JOIN allergies AS T2 ON T1.patient = T2.PATIENT WHERE T1.prefix = 'Mrs.' AND T1.first = 'Saundra' AND T1.last = 'Monahan'