Table schema:
CREATE TABLE Participants_in_Events (Participant_ID VARCHAR, Event_ID VARCHAR); CREATE TABLE services (Service_Type_Code VARCHAR, service_id VARCHAR); CREATE TABLE EVENTS (service_id VARCHAR, Event_ID VARCHAR); CREATE TABLE participants (Participant_ID VARCHAR)

Question: Which service id and type has the least number of participants?
SQL: SELECT T3.service_id, T4.Service_Type_Code FROM participants AS T1 JOIN Participants_in_Events AS T2 ON T1.Participant_ID = T2.Participant_ID JOIN EVENTS AS T3 ON T2.Event_ID = T3.Event_ID JOIN services AS T4 ON T3.service_id = T4.service_id GROUP BY T3.service_id ORDER BY COUNT(*) LIMIT 1