import bisect


def _get_exon_start_position(position, exons):
    """
    Given an intronic position (start), get its appropriate exon position.

    :arg int position: Zero-based position.
    :arg list exons: Flattened exons list.
    :returns: Exon position.
    :rtype: int
    """
    return exons[bisect.bisect_right(exons, position)]