#!/bin/python3
import sys, re
from pprint import pprint

input_f = 'test'
part = 2


#########################################
#                                       #
#              Part 1                   #
#                                       #
#########################################
if part == 1:
    children = []
    mains = []
    with open(input_f)as file:
        for line in file:
            l = line.rstrip()
            if '->' in l:
                x = l.split('->')
                for i in x[1].split(','):
                    children.append(i.strip())
                match = re.match(r"^(\S+)",x[0])
                if match:
                    mains.append(match.group(1))

    for x in mains:
        if x not in children:
            print(x)



#########################################
#                                       #
#              Part 2                   #
#                                       #
#########################################
if part == 2:
    children = []
    mains = []
    with open(input_f)as file:
        for line in file:
            l = line.rstrip()
            if '->' in l:
                x = l.split('->')
                for i in x[1].split(','):
                    children.append(i.strip())
                match = re.match(r"^(\S+)",x[0])
                if match:
                    mains.append(match.group(1))