def human_time(s):
    """ Return human-readable string of n seconds

    >>> human_time(42)
    '42s'

    >>> human_time(32490)
    '9h01m30s'
    """

    if s > 3600:
        return '%ih%02im%02is' % (s / 3600, s / 60 % 60, s % 60)
    if s > 60:
        return '%im%02is' % (s / 60, s % 60)
    return '%02is' % s