in the month of december are there any flights from atlanta to denver that stop in boston 
return flights ;return #1 in  december ;return #2 from  atlanta ;return #3 to denver ;return #4 that stop in  boston ;return number of  #5 ;return if #6 is at least one
['select', 'filter', 'filter', 'filter', 'filter', 'aggregate', 'boolean']