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: Runtime Error)

#require "pry-byebug"
S=gets.chomp

len = S.length / 2
ary = S.split("")
cycle = true
len.times do |n|
 f = ary.shift
 e = ary.pop
 if f != e
  cycle = false
  break
 end
end
if cycle == false
  puts "No"
  exit
end

N = S.length
end_pos = (N - 1) / 2
s_sub = S.slice(0, end_pos)
len = s_sub.length / 2
ary = s_sub.split("")
cycle = true
len.times do |n|
  f = ary.shift
  e = ary.pop
  if f != e
   cycle = false
   break
  end
end
if cycle == false
  puts "No"
  exit
end

start_pos = (N + 3) / 2
s_sub = S.slice(start_pos)
len = s_sub.length / 2
ary = s_sub.split("")
cycle = true
len.times do |n|
  f = ary.shift
  e = ary.pop
  if f != e
   cycle = false
   break
  end
end
if cycle == false
  puts "No"
  exit
end

puts "Yes"