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 Python (3.4.3) (judge verdict: Accepted)

s = input()
rs = s[::-1]

# 回文チェック
for i in range(len(s)):
    if s[i] != rs[i]:
        print('No')
        exit(0)

# 前半の回文チェック
zs = s[:len(s)//2]
rzs = zs[::-1]
for i in range(len(zs)):
    if zs[i] != rzs[i]:
        print('No')
        exit(0)

# 後半の回文チェック
ks = s[len(s)//2+1:]
rks = ks[::-1]
for i in range(len(ks)):
    if ks[i] != rks[i]:
        print('No')
        exit(0)

print('Yes')