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 Common Lisp (SBCL 1.1.14) (judge verdict: Wrong Answer)

(defun string-palindrome ()
  (let* ((s (read-line))
         (n (length s))
         (sr (reverse s))
         (ans "No"))
    (if (string= s sr)
        (if (and (oddp (/ (1- n) 2)) (string= (subseq s 0 (/ (1- n) 2)) (subseq sr 0 (/ (1- n) 2))))
            (if (and (oddp (/ (+ n 3) 2)) (string= (subseq s (/ (+ n 3) 2) n) (subseq sr (/ (+ n 3) 2) n)))
                (setf ans "Yes"))))
    ans))

(format t "~A~%" (string-palindrome))