What is the maximum mpg of the cars that had 8 cylinders or that were produced before 1980?
return cars ;return #1 that  had 8 cylinders ;return #1 that  were produced before 1980 ;return #2 or  #3 ;return mpg of  #4 ;return the  maximum of  #5
['select', 'filter', 'filter', 'union', 'project', 'aggregate']