from itertools import combinations as comb
def cross_p(p1,p2):
	return p1[0]*p2[1]-p1[1]*p2[0]
def vec_s(p1,p2):
	return (p1[0]-p2[0],p1[1]-p2[1])
def check(c):
	for i in range(5):
		if i in c:
			continue
		d = [cross_p(vec_s(p[c[(j+1)%3]],p[c[j]]),vec_s(p[i],p[c[(j+1)%3]])) for j in range(3)]
		if (d[0] >= 0 and d[1] >= 0 and d[2] >= 0) or (d[0] <= 0 and d[1] <= 0 and d[2] <= 0):
			return True
	return False
p = [map(int,raw_input().split()) for i in range(5)]
for c in comb(range(5),3):
	if check(c):
		print "NO"
		break
else:
	print "YES"