import itertools

D = list(map(int, input().split()))
for lst in itertools.permutations(D):
    ok = True
    for i in range(1, 6):
        a = lst[i - 1]
        b = lst[i]
        c = lst[i + 1]
        if a < c < b or b < a < c:
            pass
        else:
            ok = False
            break
    if ok:
        print("YES")
        exit()
else:
    print("NO")