How many more natural streams were named arroyo compared to rio and wash combined?
return natural streams ;return #1 named arroyo ;return #1 named rio ;return #1 named wash ;return the  number of  #2 ;return the  number of  #3 ;return the  number of  #4 ;return the  sum of #6 and  #7 ;return the  difference of #5 and  #8
['select', 'filter', 'filter', 'filter', 'aggregate', 'aggregate', 'aggregate', 'arithmetic', 'arithmetic']