Task: Text to Code
Input (English): SQL: SELECT T2.first_name , T2.last_name FROM Charges AS T1 JOIN Professionals AS T2 WHERE T1.charge_amount < ( SELECT Avg ( T1.charge_amount ) FROM Charges AS T1 )
Feedback: Change charge amount in charges with cost of treatment of treatments in step 1 and charge amount with Treatments's cost of treatment in step 3.
Output (English): SELECT DISTINCT T1.first_name ,  T1.last_name FROM Professionals AS T1 JOIN Treatments AS T2 WHERE cost_of_treatment  <  ( SELECT avg(cost_of_treatment) FROM Treatments )