How many rows does the following query return?CREATE TABLE r(a INT, b TEXT); INSERT INTO r VALUES (1,'x'),(2,'y'),(3,'x'); CREATE TABLE s(b…

How many rows does the following query return?

CREATE TABLE r(a INT, b TEXT);
INSERT INTO r VALUES (1,'x'),(2,'y'),(3,'x');
CREATE TABLE s(b TEXT, c INT);
INSERT INTO s VALUES ('x',10),('x',20),('z',30);
SELECT COUNT(*) FROM r NATURAL JOIN s;