An agency organizes conferences devoted to different topics. The following relations are part of the agency database. Each conference has exactly one organizing committee, Famous scientists are invited to serve as organizing committee members. The same person can serve on several committees playing different roles. Each committee comprises several people. CREATE TABLE Conference (ConfiD char(6) Title varchar2(20), Location varchar2(20), Sdate date, PRIMARY KEY (ConflD)); ConfiD - conference ID, Title - conference title, Location - the city where the conference is held, Sdate - starting date of the conference. CREATE TABLE Org_member (MID char(6), Name varchar2(20), Occupation varchar(15), PRIMARY KEY (MID)); MID - member's ID, Name - member's name, Occupation - member's occupation (e.g. professor, engineer, or physician, etc.) CREATE TABLE Serves (ConfiD char(6), MID char(6), Role char(9), PRIMARY KEY (ConfiD, MID), FOREIGN KEY (ConflD) REFERENCES Conference, FOREIGN KEY (MID) REFERENCES Org_member); Role - the role of a particular person in a given conference's organizing committee (e.g. a chair, a secretary, or a regular member). Write the following query using RELATIONAL ALGEBRA: Find the names of members who served on the committees of both conferences held in Sydney and those held in Barcelona