i want to convert it to relational algebra

SQL Statement: SELECT FNAME, SSN, ReservatioNum, ServiceName, Date_Of_Reservations FROM EMPLOYEE NATURAL JOIN RESERVATIONS; SQL Statement: SELECT r. ReservatioNum, r. ServiceName, r. Cname, s.Type, s.Price FROM RESERVATIONS r JOIN SERVICE s ON(r. ReservatioNum =s. Reservationum); SQL Statement: SELECT e.SSN, s.ServiceID FROM EMPLOYEE e JOIN SERVICE S ON(e.Fname=s.Name)