var x1,y1,x2,y2: real;

begin

readln(x1,y1,x2,y2);

if y1*y2<0 then write('да') else write('нет');

end.

Verified answer

x1y1 = [int(i) for i in input().split()]

x2y2 = [int(i) for i in input().split()]

if x1y1[1] > 0 and x2y2[1] > 0:

   print('Нет')

elif x1y1[1] < 0 and x2y2[1] < 0:

   print('Нет')

else:

   print('Да')