How many more elephants lived in Central Africa in 1989 compared to East Africa?
return Central Africa ;return East Africa ;return elephants in  1989 of #1 ;return elephants in  1989 of #2 ;return number of  #3 ;return number of  #4 ;return the  difference of #5 and  #6
['select', 'select', 'project', 'project', 'aggregate', 'aggregate', 'arithmetic']