ax,ay = map(int,input().split())
bx,by = map(int,input().split())
cx,cy = map(int,input().split())
dx,dy = map(int,input().split())
a = complex(ax,ay)
b = complex(bx,by)
c = complex(cx,cy)
d = complex(dx,dy)
ans = ((a-c)*(b-d))/((a-d)*(b-c))
ans1 = (a-c)/(b-c)
ans2 = (a-d)/(b-d)
# print(ans)
# print(ans1)
# print(ans2)
if (abs(ans.imag) >= 0.000000000000001) or (abs(ans1.imag) <= 0.000000000000001 and abs(ans2.imag) <= 0.000000000000001):
    print("NO")
else:
    print("YES")