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: Wrong Answer)


s = input()
n = len(s)

flag = True
# 回分チェック
if not s[:int(n/2)] == s[int(n/2)+1:]:
    flag = False

# 2チェック
chk = s[:int((n-1)/2)]
len_ = len(chk)
if not len_ % 2 == 0:
    a = chk[:int(len_/2)]
    b = chk[int(len_/2)+1:]
else:
    a = chk[:int(len_/2)]
    b = chk[int(len_/2):]
len_ = len(chk)
if not a == b:
    flag = False
# 3チェック
chk = s[int((n+3)/2)-1:]
len_ = len(chk)
if not len_ % 2 == 0:
    a = chk[:int(len_/2)]
    b = chk[int(len_/2)+1:]
else:
    a = chk[:int(len_/2)]
    b = chk[int(len_/2):]
len_ = len(chk)
if not a == b:
    flag = False
if flag:
    print('Yes')
else:
    print('No')

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