import sys
from itertools import permutations
sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


D = LI()
for p in list(permutations([i for i in range(7)],7)):
    X = [D[p[i]] for i in range(7)]
    for i in range(5):
        x,y,z = X[i:i+3]
        if not (x < z < y or y < x < z):
            break
    else:
        print('YES')
        break
else:
    print('NO')