def overflow_format(num, overflow):
    """
    Returns string of the given integer. If the integer is large than given overflow, '{overflow}+' is returned
    :param num: int
    :param overflow: int
    :return: str
    """

    if not isinstance(num, int):
        raise ValueError('Input argument "num" should be int type, but get "{}"'.format(type(num)))
    if not isinstance(overflow, int):
        raise ValueError('Input argument "overflow" should be int type, but get "{}"'.format(type(num)))

    return str(num) if num <= overflow else '{}+'.format(overflow)