program W
implicit none
integer::Q(9,9)
integer::N
integer::x1,y1,x2,y2
integer::i
Q=0
Q(2,8)=1;Q(3,9)=2;Q(7,9)=3
read*,N
do i=1,N
  read*,x1,y1,x2,y2
  Q(x1,y1)=xor(Q(x1,y1),Q(x2,y2))
  Q(x2,y2)=xor(Q(x1,y1),Q(x2,y2))
  Q(x1,y1)=xor(Q(x1,y1),Q(x2,y2))
end do
print"(A)",trim(merge("YES","NO ",Q(5,8)==1.and.Q(4,8)==2.and.Q(6,8)==3))
end program W