CF-798A

A. Mike and palindrome

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

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.

Input

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

Output

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

Examples

input

abccaa

output

YES

input

abbcca

output

NO

input

abcda

output

YES

 

题意：

能否恰好改变一个字符，使字符串变成一个回文串。

 

注意当有奇数个字符且本身为回文串时可以只改变中间的字符。

要满足动一次的条件

 

AC代码：

#include<bits/stdc++.h>
using namespace std;

int main(){
    string s;
    int cnt=0;
    cin>>s;
    for(int i=0,j=s.size()-1;i<j;i++,j--){
        if(s[i]!=s[j]){
            if(cnt==1){
                cout<<"NO"<<endl;
                return 0;
            }
            cnt=1;
        }
    }
    if(cnt==1||s.size()%2) 
    cout<<"YES"<<endl;
    else
    cout<<"NO"<<endl;
    return 0;
}