#!/usr/bin/env ruby

require 'pp'

class Array
  def to_empty_hash
    h = {}
    self.each do |el|
      h[el] = nil
    end
    return h
  end
end

input = $stdin.readlines.map(&:chomp)

hash = {}

input.each do |line|
  me, them = line.split(" -> ")
  _, name, weight = me.match(/([a-z]+) \((\d+)\)/).to_a
  children = them.nil? ? [] : them.split(", ")

  hash[name.intern] = {
    :weight => weight,
    :remove => false,
    :children => children.map(&:intern).to_empty_hash
  }
end

hash.each do |key, value|
  value[:children].each do |ckey, cvalue|
    if cvalue.nil? then
      value[:children][ckey] = hash[ckey].dup
      hash[ckey][:remove] = true
    end
  end
end

hash = hash.reject { |key, value|
  value[:remove]
}

puts hash.keys.first