Codeforces 505A. Mr. Kitayuta's Gift 水

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本文介绍了一个编程挑战：通过向给定字符串中插入一个字母使其成为回文串。文章提供了输入输出示例，并展示了实现这一目标的一种算法思路。

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Mr. Kitayuta has kindly given you a string s consisting of lowercase English letters. You are asked to insert exactly one lowercase English letter into s to make it a palindrome. A palindrome is a string that reads the same forward and backward. For example, "noon", "testset" and "a" are all palindromes, while "test" and "kitayuta" are not.

You can choose any lowercase English letter, and insert it to any position of s, possibly to the beginning or the end of s. You have to insert a letter even if the given string is already a palindrome.

If it is possible to insert one lowercase English letter into s so that the resulting string will be a palindrome, print the string after the insertion. Otherwise, print "NA" (without quotes, case-sensitive). In case there is more than one palindrome that can be obtained, you are allowed to print any of them.

Input

The only line of the input contains a string s (1 ≤ |s| ≤ 10). Each character in s is a lowercase English letter.

Output

If it is possible to turn s into a palindrome by inserting one lowercase English letter, print the resulting string in a single line. Otherwise, print "NA" (without quotes, case-sensitive). In case there is more than one solution, any of them will be accepted.

Sample test(s)

input
revive

output
reviver

input
ee

output
eye

input
kitayuta

output
NA

Note

For the first sample, insert 'r' to the end of "revive" to obtain a palindrome "reviver".

For the second sample, there is more than one solution. For example, "eve" will also be accepted.

For the third sample, it is not possible to turn "kitayuta" into a palindrome by just inserting one letter.

import sys 

s = raw_input()
n = len(s)

for i in range(0,n+1):
	s1 = s[:i]
	s2 = s[i:]
	for j in range(ord('a'),ord('z')+1):
		temp1 = s1 + chr(j) + s2
		temp2 = temp1[::-1]
		if temp1 == temp2:
			print temp1
			sys.exit()

print "NA"