def vcp(el_num: int) ->str:
    """Determine volume coverage pattern by number of scans."""
    if el_num == 5:
        task_name = 'VCP31'
    elif el_num == 9:
        task_name = 'VCP21'
    elif el_num == 14:
        task_name = 'VCP11'
    else:
        task_name = 'Unknown'
    return task_name
