How to i make a procedure in PostgreSQL using IF-statements and a print?

Question

CREATE OR REPLACE PROCEDURE number_students()
LANGUAGE 'plpgsql'
AS $BODY$
BEGIN
IF (SELECT COUNT(student_id) FROM student)
IF (number > 25) THEN
SET MESSAGE_TEXT = 'enough students';
COMMIT;
END;
$BODY$;
CALL number_students();