Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Medication ( Code VARCHAR, name VARCHAR )
TABLE: CREATE TABLE patient ( SSN VARCHAR )
TABLE: CREATE TABLE Prescribes ( patient VARCHAR, Medication VARCHAR )

### Question ###
Find the number of patients who are not using the medication of Procrastin-X.

### Accurate SQL ###

SELECT COUNT(*) FROM patient WHERE NOT SSN IN (SELECT T1.patient FROM Prescribes AS T1 JOIN Medication AS T2 ON T1.Medication = T2.Code WHERE T2.name = 'Procrastin-X')