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: Runtime Error)

#include<stdio.h>
#include<string.h>

int main(void)
{
   int n, i, flag;
   char s[100];
   flag=1;
   scanf("%s",s[100]);
   n=strlen(s);
   for(i=0; i<n/2; i++){
      if(s[i]!=s[n-1-i])
         flag=0;
      if(flag==0)
         i=n;
   }
   if(flag==1)
      for(i=0; i<n/2; i++){
      if(s[i]!=s[(n-3)/2-i])
         flag=0;
      if(flag==0)
         i=n;
   }
   if(flag==1)
      for(i=(n+1)/2;i<n;i++){
         if(s[i]!=s[n-1-i]) flag=0;
         if(flag==0) i=n;
      }

   if(flag==1) printf("Yes\n");
   else     printf("No\n");

   return 0;
}