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 C (GCC 5.4.1) (judge verdict: Accepted)

// ABC 159-B
// 2020.3.24 bal4u

#include <stdio.h>
#include <string.h>

int isPalin(char *s, int n) {
	int i = 0, j = n - 1;
	while (i < j) {
		if (s[i] != s[j]) return 0;
		i++, j--;
	}
	return 1;
}

char S[105]; int N;

int main()
{
	int t;
	scanf("%s", S);
	N = strlen(S);
	t = (N+3)/2-1;
	puts((isPalin(S, N) && isPalin(S, (N-1)/2)
	    && isPalin(S+t, N-t))? "Yes": "No");
	return 0;
}