For the only Yelp business in "Yuma" city, how many "medium" reviews did it get?
medium reviews refers to review_length = 'Medium';
SELECT COUNT(T2.review_length) FROM Business AS T1 INNER JOIN Reviews AS T2 ON T1.business_id = T2.business_id WHERE T1.city LIKE 'Yuma' AND T2.review_length LIKE 'Medium'