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)

def palindrome?(word)
    word = word.to_s
    size = word.length / 2
    return ( word[0..size] == word.reverse[0..size] )
end

hantei = 1
string = gets.chomp

unless palindrome?(string) then
    hantei = 0
end

stringArr = string.chars
wordsize = stringArr.size
mae = stringArr.slice(0..((wordsize - 1)/2)-1 ).join

unless palindrome?(mae) then
    hantei = 0 
end
ato = stringArr.slice(((wordsize + 3)/2)-1 .. -1 ).join
unless palindrome?(ato) then
    hantei = 0 
end

if hantei == 1  
  puts "Yes"
  else
  puts "No"
end