SELECT T2.name , T2.country FROM exhibition AS T1 JOIN artist AS T2 ON T1.artist_id  =  T2.artist_id GROUP BY T1.artist_id ORDER BY count(*) DESC LIMIT 1
What is the name and country for the artist with most number of exhibitions?
[Schema (values) (types)]: | theme_gallery |  artist : artist_id (text) , name (number) , country (text) , year_join (text) , age (number) | exhibition : exhibition_id (text) , year (number) , theme (text) , artist_id (text) , ticket_price (number) | exhibition_record : exhibition_id (text) , date (number) , attendance (text);