#!/usr/bin/python

import sys

def parse_sysusers_file(filename):

    users, groups = set(), set()

    for line in open(filename):

        line = line.strip()

        if not line or line.startswith('#'):

            continue

        words = line.split()

        match words[0]:

            case 'u':

                users.add(words[1])

            case 'g':

                groups.add(words[1])

            case 'm'|'r':

                continue

            case _:

                assert False

    return users, groups

setup_users, setup_groups = parse_sysusers_file(sys.argv[1])

setup_users2, setup_groups2 = parse_sysusers_file(sys.argv[2])

setup_users |= setup_users2

setup_groups |= setup_groups2

basic_users, basic_groups = parse_sysusers_file(sys.argv[3])

if d := basic_users - setup_users:

    exit(f'We have new users: {d}')

if d := basic_groups - setup_groups:

    exit(f'We have new groups: {d}')