human
Solve in Python:
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.

-----Input-----

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.

-----Output-----

In the first line, print $m$ — the number of maximum possible beautiful...
assistant
#Here is Python code to print $m$ — the number of maximum possible beautiful.

from collections import deque

if True:
    N = int(input())
    # X = [[[] for _ in range(5)] for i in range(500001)]
    X = {}
    def calc(t):
        c = 0
        v = 0
        for u in reversed(t):
            if u == "a" or u == "i" or u == "u" or u == "e" or u == "o":
                if c == 0:
                    if u == "a": v = 0
                    if u == "i": v = 1
                    if u == "u": v = 2
                    if u == "e": v = 3
                    if u == "o": v = 4
                c += 1
        if c not in X:
            X[c] = [[] for _ in range(5)]
        
        X[c][v].append(t)

    for _ in range(N):
        calc(input())
else:
    N = 14
    X = [[[], [], [], [], []], [['am', 'that'], ['this', 'is', 'first', 'mcdics', 'i'], [], ['the'], ['wow']], [[], [], ['round', 'proud'], [], []], [['hooray'], [], ['about'], [], []], [[], [], [], ['codeforces'], []]]
# print("X =", X)
A = 0
B = 0
Q = deque([])
for i in X:
    # print("X[i] =", X[i])
    # print([len(x)//2 for x in X[i]])
    a = sum([len(x)//2 for x in X[i]]) * 2
    b = sum([len(x) for x in X[i]])//2*2 - a
    A += a
    B += b
    # print("a, b, A, B =", a, b, A, B)
    for j in range(5):
        while len(X[i][j]) >= 2:
            deque.appendleft(Q, X[i][j].pop())
            deque.appendleft(Q, X[i][j].pop())
    
    for j in range(5):
        while len(X[i][j]) >= 1 and b > 0:
            deque.append(Q, X[i][j].pop())
            b -= 1
    # print("Q =", Q)

ans = min(A//2, (A+B)//4)
print(ans)
for _ in range(ans):
    print(Q.pop(), Q.popleft())
    print(Q.pop(), Q.popleft())