show me all the flights from denver and all the flights from miami that arrive at baltimore around noon 
return flights  ;return #1 from denver ;return #1 from miami ;return #2 that  arrive at baltimore ;return #3 that  arrive at baltimore ;return #4 around noon ;return #5 around noon ;return #6 ,  #7
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'filter', 'union']