#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
import itertools

# %%
import numpy as np

# %%
XY = np.array(read().split(), np.int64)
X = XY[::2]
Y = XY[1::2]

# %%


def is_edge_of_convexhull(i, j):
    b = X[i] - X[j]
    a = Y[j] - Y[i]
    c = a * X[i] + b * Y[i]
    return np.count_nonzero(a * X + b * Y - c > 0) == 3


# %%
n = 0
it = itertools.product(range(5), repeat=2)
n = sum(is_edge_of_convexhull(i, j) for i, j in it if i != j)
print('YES' if n == 5 else 'NO')