def overlaps(s1, e1, s2, e2):
    """
    >>> overlaps(2, 4, 3, 5)
    True
    >>> overlaps(2, 4, 4, 5)
    False
    >>> overlaps(2, 200, 3, 5)
    True
    >>> overlaps(3, 5, 2, 200)
    True
    >>> overlaps (3, 5, 5, 6)
    False
    >>> overlaps (5, 6, 3, 5)
    False
    >>> overlaps(2, 4, 2, 4)
    True
    """
    return not (e1 <= s2 or s1 >= e2)
