CF798A.Mike and palindrome

Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the string so that the resulting one is a palindrome.

A palindrome is a string that reads the same backward as forward, for example strings "z", "aaa", "aba", "abccba" are palindromes, but strings "codeforces", "reality", "ab" are not.

Mike 有一个仅由小写英文字母组成的字符串 $s$。他希望恰好修改该字符串中的一个字符，使得修改后得到的字符串是一个回文串。

回文串是指正读和反读都相同的字符串，例如字符串 “z”、“aaa”、“aba”、“abccba” 都是回文串，但字符串 “codeforces”、“reality”、“ab” 则不是。

The first and single line contains string s (1 ≤ |s| ≤ 15).

第一行且唯一一行包含字符串 $s$（$1 \leq |s| \leq 15$）。

Print "YES" (without quotes) if Mike can change exactly one character so that the resulting string is palindrome or "NO" (without quotes) otherwise.

如果 Mike 恰好修改一个字符就能使字符串变为回文串，则输出 "YES"（不带引号）；否则输出 "NO"（不带引号）。