Literature Lesson

题意翻译

四行诗的形态有四种：aaaa,aabb,abba,abab 其中，相同的字母表示两个单词从后往前数第k个元音之后的后缀相同（不是元音相同）。后缀都为空视为不相等。 现在，给n篇四行诗和k，输出每种四行诗的类型，如果都不是，输出NO。

题目描述

Vera adores poems. All the poems Vera knows are divided into quatrains (groups of four lines) and in each quatrain some lines contain rhymes. Let's consider that all lines in the poems consist of lowercase Latin letters (without spaces). Letters "a", "e", "i", "o", "u" are considered vowels. Two lines rhyme if their suffixes that start from the $ k $ -th vowels (counting from the end) match. If a line has less than $ k $ vowels, then such line can't rhyme with any other line. For example, if $ k=1 $ , lines $ commit $ and $ hermit $ rhyme (the corresponding suffixes equal $ it $ ), and if $ k=2 $ , they do not rhyme ( $ ommit≠ermit $ ). Today on a literature lesson Vera learned that quatrains can contain four different schemes of rhymes, namely the following ones (the same letters stand for rhyming lines): - Clerihew ( $ aabb $ ); - Alternating ( $ abab $ ); - Enclosed ( $ abba $ ). If all lines of a quatrain pairwise rhyme, then the quatrain can belong to any rhyme scheme (this situation is represented by $ aaaa $ ). If all quatrains of a poem belong to the same rhyme scheme, then we can assume that the whole poem belongs to this rhyme scheme. If in each quatrain all lines pairwise rhyme, then the rhyme scheme of the poem is $ aaaa $ . Let us note that it doesn't matter whether lines from different quatrains rhyme with each other or not. In other words, it is possible that different quatrains aren't connected by a rhyme. Vera got a long poem as a home task. The girl has to analyse it and find the poem rhyme scheme. Help Vera cope with the task.

输入输出格式

输入格式

The first line contains two integers $ n $ and $ k $ ( $ 1<=n<=2500 $ , $ 1<=k<=5 $ ) — the number of quatrains in the poem and the vowel's number, correspondingly. Next $ 4n $ lines contain the poem. Each line is not empty and only consists of small Latin letters. The total length of the lines does not exceed $ 10^{4} $ . If we assume that the lines are numbered starting from 1, then the first quatrain contains lines number $ 1 $ , $ 2 $ , $ 3 $ , $ 4 $ ; the second one contains lines number $ 5 $ , $ 6 $ , $ 7 $ , $ 8 $ ; and so on.

输出格式

Print the rhyme scheme of the poem as "aabb", "abab", "abba", "aaaa"; or "NO" if the poem does not belong to any of the above mentioned schemes.

输入输出样例

输入样例 #1

1 1
day
may
sun
fun

输出样例 #1

aabb

输入样例 #2

1 1
day
may
gray
way

输出样例 #2

aaaa

输入样例 #3

2 1
a
a
a
a
a
a
e
e

输出样例 #3

aabb

输入样例 #4

2 1
day
may
sun
fun
test
hill
fest
thrill

输出样例 #4

NO

说明

In the last sample both quatrains have rhymes but finding the common scheme is impossible, so the answer is "NO".