How many more people lived in Kabuls by 1979 compared to 1940?
return Kabuls ;return people of #1 ;return #2 in  1979 ;return #2 in  1940 ;return number of  #3 ;return number of  #4 ;return difference of #5 and  #6
['select', 'project', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']