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)

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

int main()
{
	char s[128];
	gets(s);
	int len;
	len=strlen(s);
	int l,r;
	l=0;r=(len-1)/2-1;
	while (l<r)
		if (s[l]==s[r]) 
		{
			++l;--r;
		}
		else break;
	if (l<r) 
	{ 
		printf("No"); 
		return 0;
	}
	l=(len+3)/2-1;r=len-1;
	while (l<r)
		if (s[l]==s[r]) 
		{
			++l;--r;
		}
		else break;
	if (l<r) 
	{ 
		printf("No"); 
		return 0;
	}
	l=0;r=len-1;
	while (l<r)
		if (s[l]==s[r]) 
		{
			++l;--r;
		}
		else break;
	if (l<r) 
	{ 
		printf("No"); 
		return 0;
	}
	printf("Yes");
	return 0;
}