class Vector:
    def __init__(self, a, b):
        self.x = b.x - a.x
        self.y = b.y - a.y

    def __mul__(self, vect):
        return self.x * vect.x + self.y * vect.y
    __rmul__ = __mul__

    def __str__(self):
        return '(' + str(self.x) + ',' + str(self.y) + ')'

    def __pow__(self, vect):
        return self.x * vect.y - vect.x * self.y


class Point:
    def __init__ (self, a, b):
        self.x = a
        self.y = b
    __str__ = Vector.__str__


x1, y1, x2, y2, x3, y3 = map(int, input().split())
A = Point(x1, y1)
B = Point(x2, y2)
C = Point(x3, y3)
first_vector = Vector(B, C)
second_vector = Vector(B, A)
third_vector = Vector(A, B)
forth_vector = Vector(A, C)
if first_vector ** second_vector == 0:
    if third_vector * forth_vector <= 0:
        print("YES")
    else:
        print("NO")
else:
    print("NO")