CF1182C.Beautiful Lyrics

You are given $n$ words, each of which consists of lowercase alphabet letters. Each word contains at least one vowel. You are going to choose some of the given words and make as many beautiful lyrics as possible.

Each lyric consists of two lines. Each line consists of two words separated by whitespace.

A lyric is beautiful if and only if it satisfies all conditions below.

• The number of vowels in the first word of the first line is the same as the number of vowels in the first word of the second line.
• The number of vowels in the second word of the first line is the same as the number of vowels in the second word of the second line.
• The last vowel of the first line is the same as the last vowel of the second line. Note that there may be consonants after the vowel.

Also, letters "a", "e", "o", "i", and "u" are vowels. Note that "y" is never vowel.

For example of a beautiful lyric,

"hello hellooowww"

"whatsup yowowowow"

is a beautiful lyric because there are two vowels each in "hello" and "whatsup", four vowels each in "hellooowww" and "yowowowow" (keep in mind that "y" is not a vowel), and the last vowel of each line is "o".

For example of a not beautiful lyric,

"hey man"

"iam mcdic"

is not a beautiful lyric because "hey" and "iam" don't have same number of vowels and the last vowels of two lines are different ("a" in the first and "i" in the second).

How many beautiful lyrics can you write from given words? Note that you cannot use a word more times than it is given to you. For example, if a word is given three times, you can use it at most three times.

你将得到 $n$ 个单词，每个单词均由小写英文字母组成。每个单词中至少包含一个元音字母。你需要从给定的单词中选出若干个，尽可能多地创作出“优美的歌词”（beautiful lyrics）。

每首歌词由两行组成，每行由两个单词构成，单词之间以空格分隔。

当且仅当满足以下所有条件时，一首歌词才是优美的：

• 第一行第一个单词中的元音字母个数，等于第二行第一个单词中的元音字母个数；
• 第一行第二个单词中的元音字母个数，等于第二行第二个单词中的元音字母个数；
• 第一行中最后一个元音字母，与第二行中最后一个元音字母相同。（注意：该元音字母之后可能还跟有辅音字母。）

其中，字母 "a"、"e"、"o"、"i" 和 "u" 被视为元音字母；注意 "y" 永远不被视为元音字母。

例如，以下是一首优美的歌词：

hello hellooowww
whatsup yowowowow

它是优美的，因为："hello" 和 "whatsup" 各含 2 个元音字母；"hellooowww" 和 "yowowowow" 各含 4 个元音字母（注意 "y" 不是元音）；且每行的最后一个元音字母均为 "o"。

再例如，以下不是一首优美的歌词：

hey man
iam mcdic

它不优美，因为 "hey" 和 "iam" 的元音字母个数不同，且两行最后一个元音字母也不同（第一行为 "a"，第二行为 "i"）。

你最多能用给定的单词创作出多少首优美的歌词？注意：每个单词最多只能使用其在输入中出现的次数。例如，若某个单词在输入中出现了三次，则你最多可使用它三次。

The first line contains single integer $n$ ($1 \le n \le 10^{5}$) — the number of words.

The $i$-th of the next $n$ lines contains string $s_{i}$ consisting lowercase alphabet letters — the $i$-th word. It is guaranteed that the sum of the total word length is equal or less than $10^{6}$. Each word contains at least one vowel.

第一行包含一个整数 $n$（$1 \le n \le 10^{5}$）—— 单词的个数。

接下来的 $n$ 行中，第 $i$ 行包含一个由小写英文字母组成的字符串 $s_{i}$ —— 第 $i$ 个单词。保证所有单词长度之和不超过 $10^{6}$。每个单词至少包含一个元音字母。

In the first line, print $m$ — the number of maximum possible beautiful lyrics.

In next $2m$ lines, print $m$ beautiful lyrics (two lines per lyric).

If there are multiple answers, print any.

第一行输出 $m$ —— 最多可能的优美歌词数量。

接下来的 $2m$ 行中，输出 $m$ 段优美歌词（每段歌词占两行）。

若存在多种答案，输出任意一种即可。

In the first example, those beautiful lyrics are one of the possible answers. Let's look at the first lyric on the sample output of the first example. "about proud hooray round" forms a beautiful lyric because "about" and "hooray" have same number of vowels, "proud" and "round" have same number of vowels, and both lines have same last vowel. On the other hand, you cannot form any beautiful lyric with the word "codeforces".

In the second example, you cannot form any beautiful lyric from given words.

In the third example, you can use the word "same" up to three times.

在第一个样例中，那些优美的歌词是可能的答案之一。我们来看第一个样例输出中的第一句歌词：“about proud hooray round”构成了一段优美的歌词，因为“about”与“hooray”的元音字母数量相同，“proud”与“round”的元音字母数量也相同，且两行的最后一个元音字母相同。另一方面，你无法用单词“codeforces”构造出任何优美的歌词。

在第二个样例中，你无法用给定的单词构造出任何优美的歌词。

在第三个样例中，你可以最多使用单词“same”三次。