#!/usr/bin/env python3
import re
from collections import defaultdict

lines = (x.strip() for x in open("input.txt"))
REGEX = re.compile(r"((?:[a-z]+ )+)\(contains (.*)\)")

possible_ingredients = dict()
count = defaultdict(int)

for line in lines:
    ingredients, allergens = REGEX.match(line).groups()
    ingredients = set(ingredients.strip().split())
    for ing in ingredients:
        count[ing] += 1
    allergens = allergens.strip().split(", ")
    for allergen in allergens:
        if allergen in possible_ingredients:
            possible_ingredients[allergen].intersection_update(ingredients)
        else:
            possible_ingredients[allergen] = set(ingredients)

valids = set.union(*possible_ingredients.values())

done = dict()
while len(possible_ingredients):
    for allergen, ingredients in possible_ingredients.copy().items():
        if len(ingredients) == 1:
            ing = ingredients.pop()
            done[allergen] = ing
            possible_ingredients.pop(allergen)
            for ings in possible_ingredients.values():
                ings.discard(ing)


print(",".join(done[x] for x in sorted(done.keys())))