import itertools
D = list(map(int, input().split()))

def hantei(l):
    for p in range(5):
        if l[p] < l[p+1] > l[p+2] or l[p] > l[p+1] < l[p+2]:
            if l[p] < l[p+2]:
                continue
            else:
                return False
        else:
            return False
    return True

for retsu in itertools.permutations(D, 7):
    if hantei(list(retsu)):
        print("YES")
        exit()
print("NO")