How many more H-1B1 visas were issued in 2012 than the legal limit set in the Immigration Act of 1990?
return the  Immigration Act of 1990 ;return legal limit of H-1B1 visas of  #1 ;return H-1B1 visas ;return #3 issued in  2012 ;return number of  #4 ;return the  difference of #5 and  #2
['select', 'project', 'select', 'filter', 'aggregate', 'arithmetic']