from typing import Optional
import re


def get_server_id(data: str) -> Optional[int]:
    """
    Extracts six digit id of server.
    :param data: Input data.
    :return: Server id number.
    """
    server_id = re.findall(r"#(\d{6})", data)
    if server_id:
        return int(server_id[0])
    else:
        return None