from scipy.spatial import ConvexHull, qhull

P = [tuple(map(int, input().split())) for _ in range(5)]
try:
	x = ConvexHull(P,qhull_options='QR0').simplices
	print('YES' if len(x) == 5 else 'NO')
except qhull.QhullError:
  	print('NO')