a1 <= not x(1) and not x(2) and not x(3) and not x(4) and not x(5);
   a2 <= x(1) and not x(2) and not x(4) and x(5);
   a3 <= x(1) and not x(2) and not x(3) and x(4) and x(5);
   a4 <= x(1) and not x(2) and x(3) and x(4) and not x(5);
   a5 <= not x(1) and x(2)  and x(3) and x(4) and x(5);
   a6 <= x(1) and x(2) and x(3) and not x(4) and x(5);                  -
   a7 <= not x(1) and not x(2) and x(3) and not x(4) and not x(5);
   y <= a1 or a2 or a3 or a4 or a5 or a6 or a7;

end df1;