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
l = s.length
c = "Yes"

(l/2).times {|i|
  if s[i] == s[-i-1] then
  else
    c = "No"
    break
  end
}

if c == "Yes" then
  s[0..((l/2)-1)].length.times {|i|
    if s[0..((l/2)-1)][i] == s[0..((l/2)-1)][-i-1] then
    else
      c = "No"
      break
    end
  }
end

if c == "Yes" then
  s[((l+1)/2)..(l-1)].length.times {|i|
    if s[((l+1)/2)..(l-1)][i] == s[((l+1)/2)..(l-1)][-i-1] then
    else
      c = "No"
      break
    end
  }
end
print(c)