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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

checkKaibun :: String -> Bool
checkKaibun [x] = True
checkKaibun [x, y] = x == y
checkKaibun (x:y:xs) = (x == last xs) && checkKaibun (y : init xs)

firstPart n = take ((n - 1) `div` 2)
lastPart n = drop (((n + 3) `div` 2) - 1)

solve x = checkKaibun x && (checkKaibun $ firstPart len x) && (checkKaibun $ lastPart len x)
            where 
              len = length x
main = do 
  s <- getLine
  putStrLn $ if solve s then "Yes" else "No"