How many more second-line troops than first-line troops did da Câmara's force have?
return Câmara ;return force of #1 ;return second-line troops  of #2 ;return first-line troops  of #2 ;return number of  #3 ;return number of  #4 ;return the  difference of #5 and  #6
['select', 'project', 'project', 'project', 'aggregate', 'aggregate', 'arithmetic']