题目描述

You are to find all the two-word compound words in a dictionary. A two-word compound word is a
word in the dictionary that is the concatenation of exactly two other words in the dictionary.

输入格式

Standard input consists of a number of lowercase words, one per line, in alphabetical order. There will
be no more than 120,000 words.

输出格式

Your output should contain all the compound words, one per line, in alphabetical order.

样例 1

输入

a
alien
born
less
lien
never
nevertheless
new
newborn
the
zebra

输出

alien
newborn

题目来源：19 June, 2011 - Waterloo local contest；FPS 共享题包，题包内第 4 题。保留原作者与原赛事署名。