Find the first name and gender of the student who has allergy to milk but not cat.
return students ;return #1 with  milk allergy ;return #1 with  cat allergy ;return #1 of  both #2 and not  #3 ;return first name of  #4 ;return gender of  #4 ;return #5 ,   #6
['select', 'filter', 'filter', 'intersection', 'project', 'project', 'union']