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 Ruby (2.3.3) (judge verdict: Accepted)

s = gets.chomp
arr = s.split('')
def chk (arr)
  i = 0
  j = arr.size - 1
  while i < arr.size / 2
    flg = 'no' unless arr[i] == arr[j]
    i += 1
    j -= 1
  end
  flg
end
flg = chk(arr)
if flg  == 'no'
  puts 'No'
  exit
end
arr_f = arr[0..(arr.size / 2 - 1)]
flg = chk(arr_f)
if flg  == 'no'
  puts 'No'
  exit
end
arr_s = arr[(arr.size / 2 + 1)..(arr.size - 1)]
flg = chk(arr_s)
if flg  == 'no'
  puts 'No'
  exit
else
  puts 'Yes'
end