Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
typedef long long ll;
ll comp(const void *a,const void *b)
{
  return *(ll *)b-*(ll *)a;
}
int main(void)
{
  int n=0,m=0,i=0,flag=0;
  char str[101];
  scanf("%s",str);
  while(str[i]!='\0') i++;
  for(int j=0;j<(i-1)/2;j++){
    if(str[j]!=str[i-1-j]) n++;
  }
  int k;
  k=(i+3)/2;
  for(int j=0;j<(i-1)/2;j++){
    if(str[j]!=str[k+j-1]) m++;
  }
  //printf("%d %d",n,m);
  if((n==0)&&(m==0)) printf("Yes");
  else printf("No");
  return 0;
}