eps = 1e-10

def add(a, b):
    return 0 if abs(a + b) < eps * (abs(a) + abs(b)) else a + b

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

    def __add__(self, p):
        return Point(add(self.x, p.x), add(self.y, p.y))

    def __sub__(self, p):
        return Point(add(self.x, -p.x), add(self.y, -p.y))

    def __mul__(self, d):
        return Point(self.x * d, self.y * d)

    def dot(self, p):
        return add(self.x * p.x, self.y * p.y)

    def det(self, p):
        return add(self.x * p.y, -self.y * p.x)

    def __str__(self):
        return "({}, {})".format(self.x, self.y)

from functools import cmp_to_key
def cmp_x(p, q):
    return p.x < p.y if p.x != q.x else p.y < q.y

def convex_hell(ps, n):
    """ P(x, y) : point P
        n : number of point
    """
    ps.sort(key=cmp_to_key(cmp_x))
    k = 0
    qs = [[] for _ in range(2*n)]
    for i in range(n):
        while k > 1 and (qs[k-1] - qs[k-2]).det(ps[i] - qs[k-1]) <= 0:
            k -= 1
        qs[k] = ps[i]
        k += 1

    t = k
    for i in range(n-2, -1, -1):
        while k > t and (qs[k-1] - qs[k-2]).det(ps[i] - qs[k-1]) <= 0:
            k -= 1
        qs[k] = ps[i]
        k += 1

    qs = qs[:-qs.count([])]
    return qs

qs = []
for i in range(5):
    x, y = map(int, input().split())
    qs.append(Point(x, y))
qs = convex_hell(qs, 5)
print('YES' if len(qs) == 6 else 'NO')