Write SQL query to solve given problem: Among the tweets posted from Santa Fe state in Argentina, how many of them were posted on 31st?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.TweetID) FROM twitter AS T1 INNER JOIN location AS T2 ON T1.LocationID = T2.LocationID WHERE T1.Day = 31 AND T2.State = 'Santa' AND T2.Country = 'Argentina'