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: Runtime Error)

#include <stdio.h>

int		is_parindorm(char *str, int start, int end)
{
	while (start < end)
	{
		if (str[start] != str[end])
			return (0);
		start++;
		end--;
	}
	return (1);
}

int		main()
{
	char	*str;
	int		N, mid1, mid2;

	scanf("%s\n", str);
	while (str[N])
		N++;
	N--;
	mid1 = (N - 1) / 2;
	mid2 = (N + 3) / 2;
	if (is_parindorm(str, 0, mid1) && is_parindorm(str, mid2, N) && is_parindorm(str, 0, N))
		printf("Yes\n");
	else
		printf("No\n");
	return (0);
}