Codeforces Round #410 (Div. 2) A. Mike and palindrome【判断能否只修改一个字符使其变成回文串】

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 onecharacter 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

 【代码】：

#include <bits/stdc++.h>
using namespace std;
int cnt=0;
char a[30];
int main()
{
    scanf("%s",a);
    int n=strlen(a);
    for(int i=0;i<n/2;i++)//注意！回文串只要判长度一半
    {
        if(a[i]!=a[n-i-1])
            cnt++;
    }
    //cout<<cnt<<endl;
    if(((n%2)&&(cnt==0))||cnt==1) puts("YES");//注意特判
    else puts("NO");
    return 0;
}