import itertools

def solve(As):
    for reordered in itertools.permutations(As):
        if is_valid(reordered):
            return True
    return False

def is_valid(As):
    As
    for i in range(0, 5):
        a1, a2, a3 = As[i:i+3]
        if not is_valid3(a1, a2, a3):
            return False
    return True

def is_valid3(a1, a2, a3):
    return (a1 < a3 < a2) or (a2 < a1 < a3)

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