Among all the tweets that are reshared, how many of them are posted by a user in Buenos Aires?
reshared refers to Isreshare = 'TRUE'; 'Buenos Aires' is the City
SELECT COUNT(T1.TweetID) FROM twitter AS T1 INNER JOIN location AS T2 ON T2.LocationID = T1.LocationID WHERE T2.City = 'Buenos Aires' AND T1.IsReshare = 'TRUE'