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>
int main(){
  char s[100];
  int len,i,check=0;
  scanf("%s",s);
  len=strlen(s);
  for(i=0;i<len;i++)
    if(s[i]!=s[len-i-1])
      check=1;
  for(i=0;i<(len-1)/2;i++)
    if(s[i]!=s[(len-3)/2-i] || s[i+(len+1)/2]!=s[len-i-1])
      check=1;
  if(check==1)
    printf("No\n");
  else
    printf("Yes\n");
  return 0;
}