def min_point(points, n_points):
    """
    Return the index of the closest point to (0,0)
    :param points: tuple of list for each coordinate
    :param n_points: number of points
    :return: the index of the selected point in the list
    """
    min_y_indexes = [0]
    min_y = points[1][0]

    # Find minimum y
    for k in range(1, n_points):
        if points[1][k] < min_y:
            min_y_indexes = [k]
        elif points[1][k] == min_y:
            min_y_indexes.append(k)

    # Among the points having the smallest y, find the points having the smallest x
    min_x = points[0][min_y_indexes[0]]
    min_index = min_y_indexes[0]

    for k in min_y_indexes:
        if points[0][k] < min_x:
            min_index = k

    return min_index