How many incorrect predictions did Krugman and Dowd have combined?
return predictions ;return #1 that are incorrect ;return #2 of Krugman ;return #2 of Dowd ;return number of  #3 ;return number of  #4 ;return sum of #5 and  #6
['select', 'filter', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']