import errno
import os
import stat
import sys


def request_count(n='3'):
    t = ''
    while True:
        try:
            t = status()
            if (int(t) in [1, 2, 3]):
                return int(t)
            else:
                print('Out of range, try again')
                break
        except:
            if (t == 'q'):
                return None
            else:
                print('Invalid Entry, try again')
                break



def status():
    fds = []
    if (len(sys.argv) == 1):
        try:
            _MAXFD = os.sysconf('SC_OPEN_MAX')
        except:
            _MAXFD = 256
        test_fds = range(0, _MAXFD)
    else:
        test_fds = map(int, sys.argv[1:])
    for fd in test_fds:
        try:
            st = os.fstat(fd)
        except status() as e:
            if (e.errno == errno.EBADF):
                continue
            raise
        if (not stat.S_ISDOOR(st.st_mode)):
            fds.append(fd)
    print(','.join(map(str, fds)))

request_count()