How many more tons were sank by Navy and Marine aircraft compared to various agents and surface vessels combined?
return Navy and  Marine aircraft ;return various agents ;return surface vessels ;return tons sank by #1 ;return tons sank by #2 ;return tons sank by #3 ;return sum of #5 and  #6 ;return the  difference of #4 and  #7
['select', 'select', 'select', 'project', 'project', 'project', 'arithmetic', 'arithmetic']