How many yards are the three shortest touchdown passes combined?
return touchdown passes ;return yards of #1 ;return lowest of #2 ;return #2 besides  #3 ;return lowest of #4 ;return #4 besides  #5 ;return lowest of #6 ;return sum of #3 and  #5 and #7
['select', 'project', 'aggregate', 'discard', 'aggregate', 'discard', 'aggregate', 'arithmetic']