import sys

sys.setrecursionlimit(10 ** 6)
from bisect import *
from collections import *
from heapq import *

int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline()[:-1]
def MI(): return map(int, sys.stdin.readline().split())
def MI1(): return map(int1, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
dij = [(0, 1), (1, 0), (0, -1), (-1, 0)]

# 引数xyは[(3,2),(-1,0),(-2,-4),(0,8)]のような座標のリスト
# 元のxyもソートされてしまうので注意

def ConvexHull(xy):
    def NG(x, y):
        x0, y0 = res[-2]
        x1, y1 = res[-1]
        return (x - x0) * (y1 - y0) - (x1 - x0) * (y - y0) >= 0

    res = []
    xy.sort()
    for x, y in xy:
        while len(res) > 1 and NG(x, y): res.pop()
        res.append((x, y))
    under_n = len(res)
    for x, y in xy[-2::-1]:
        while len(res) > under_n and NG(x, y): res.pop()
        res.append((x, y))
    return res[:-1]

def main():
    xy=[LI() for _ in range(5)]
    if len(ConvexHull(xy))==5:print("YES")
    else:print("NO")

main()