A - Mike and palindrome

Posted 2020-09-16

A - 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.

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.

Example

Input

abccaa

Output

YES

Input

abbcca

Output

NO

Input

abcda

Output

YES
题意：输入一个字符串，如果仅仅更改一个字符串能使字符串是回文就输出YES，否则输出NO；
题解：分类讨论，如果字符串长度为偶数，对折比较只能有一对字符串不同；如果是奇数，对折比较有一对或零对字符串不同；
代码：

#include<iostream>
#include<cstring>
using namespace std;
int main()
{
    char str[20];
    int i,l,j;
    while(cin>>str)
    {
        j=0;
        l=strlen(str);
        for(i=0;i<l/2;i++)
        {
            if(str[i]==str[l-i-1])
                j++;
        }
        if(l%2==1)
        {
            if(j==l/2||j==l/2-1)
                cout<<"YES"<<endl;
            else
                cout<<"NO"<<endl;
        }
        else
        {
            if(j==l/2-1)
                cout<<"YES"<<endl;
            else
                cout<<"NO"<<endl;
        }
    }
}