question: What is the name and country for the artist with most number of exhibitions?
#1 return artists 
#2 return exhibitions of  #1 
#3 return number of  #2 for each  #1 
#4 return #1 where #3 is  highest 
#5 return name of  #4 
#6 return country of  #4 
#7 return #5 ,  #6