def formatter(ms):
    """
    formats the ms into seconds and ms
    :param ms: the number of ms
    :return: a string representing the same amount, but now represented in seconds and ms.
    """
    sec = int(ms) // 1000
    ms = int(ms) % 1000
    if sec == 0:
        return '{0}ms'.format(ms)
    return '{0}.{1}s'.format(sec, ms)