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 9.2.1) (judge verdict: Accepted)

#include <stdio.h>

int is_palindrome(char s[], int l)
{
	int i;
	for (i = 0; i < l / 2; i++) if (s[i] != s[l-1-i]) break;
	if (i < l / 2) return 0;
	else return 1;
}

int main()
{
	char S[100];
	scanf("%s", S);

	int i, l;
	for (l = 0; S[l] != 0; l++);
	if (is_palindrome(S, l) + is_palindrome(S, (l - 1) / 2) + is_palindrome(&(S[(l+1)/2]), (l - 1) / 2) == 3) printf("Yes\n");
	else printf("No\n");
	fflush(stdout);
	return 0;
}