import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import itertools

*D, = map(int,read().split())

def is_kadomatsu(a,b,c):
    if a >= c:
        return False
    return (a > b < c) or (a < b > c)

def is_kadomatsu_seq(A):
    return all(is_kadomatsu(a,b,c) for a,b,c in zip(A,A[1:],A[2:]))

if any(is_kadomatsu_seq(p) for p in itertools.permutations(D)):
    answer = 'YES'
else:
    answer = 'NO'

print(answer)