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: Runtime Error)

s = input()

y = s[len(s) // 2]


str(s)
s_list = s[y:]
s_list.pop(0)
try:
    for u in s:
        if s.count(u) == 1:
            x = u
        elif len(s_list) == 1:
            r = len(s_list) // 2
            x = s_list[r]

    str(s_list)
    s_list = s[x:]
except NameError:
    print("Yes")
    exit()

if s_list[0] == s_list[1]:
    print("Yes")
else:
    print("No")