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


def cross(v1, v2):
    return v1.x * v2.y - v2.x * v1.y


def main():
    Ax, Ay = map(int, input().split())
    Ox, Oy = map(int, input().split())
    Bx, By = map(int, input().split())
    Px, Py = map(int, input().split())

    OP = Vector(Px - Ox, Py - Oy)
    OA = Vector(Ax - Ox, Ay - Oy)
    OB = Vector(Bx - Ox, By - Oy)

    if cross(OB, OA) < 0:
        if cross(OA, OP) >= 0 and cross(OP, OB) >= 0:
            print('YES')
        else:
            print('NO')
    else:
        if cross(OB, OP) >= 0 and cross(OP, OA) >= 0:
            print('YES')
        else:
            print('NO')
main()