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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program ABC159B
    implicit none
    integer(8)::i,N,flg
    character(99)::S
    read*,S
    N=len_trim(S)
    flg=0

    do i=1,N/2
        if(S(i:i)/=S(N-i+1:N-i+1))flg=1
    end do

    do i=1,N/4
        if(S(i:i)/=S(N/2-i+1:N/2-i+1))flg=1
        if(S(N/2+1+i:N/2+1+i)/=S(N-i+1:N-i+1))flg=1
    end do
    if(flg==0)print'(A)',"Yes"
    if(flg==1)print'(A)',"No"
end program ABC159B