from itertools import permutations


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


def solve():
    for xs in permutations(DD):
        for i in range(5):
            a, b, c = xs[i:i+3]
            if not is_kadomatu(a, b, c) or a > c:
                break
        else:
            return True

    return False


DD = list(map(int, input().split()))
if solve():
    print('YES')
else:
    print('NO')