CREATE TABLE Services (
Service_ID INTEGER NOT NULL,
Service_Type_Code CHAR(15) NOT NULL,
PRIMARY KEY (Service_ID)
)

CREATE TABLE Participants (
Participant_ID INTEGER NOT NULL,
Participant_Type_Code CHAR(15) NOT NULL,
Participant_Details VARCHAR(255),
PRIMARY KEY (Participant_ID)
)

CREATE TABLE Events (
Event_ID INTEGER NOT NULL,
Service_ID INTEGER NOT NULL,
Event_Details VARCHAR(255),
PRIMARY KEY (Event_ID),
FOREIGN KEY (Service_ID) REFERENCES Services (Service_ID)
)

CREATE TABLE Participants_in_Events (
Event_ID INTEGER NOT NULL,
Participant_ID INTEGER NOT NULL,
PRIMARY KEY (Event_ID, Participant_ID),
FOREIGN KEY (Participant_ID) REFERENCES Participants (Participant_ID),
FOREIGN KEY (Event_ID) REFERENCES Events (Event_ID)
)
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(*) ASC LIMIT 1
Which service id and type has the least number of participants?