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: Wrong Answer)

#include <stdio.h>
int main(void)
{
	char s[99];
	int n, i, m, con = 0;
	for(n = 0; n < 99; n++){
		s[n] = '0';
	}
	
	scanf("%s", &s);
	
	n = 0;
	while(s[n] != '0'){
		n++;
	}
	n--;
//	printf("n=%d\n", n);
	
	i = n / 2;
//	printf("i=%d\n", i);
	
	for(m = 0; m < i; m++){
		if(s[m] != s[i - m - 1]){
			con++;
		}
		if(s[m] != s[m + i + 1]){
			con++;
		}
	}
	
	if(con == 0){
		printf("Yes");
	}
	else{
		printf("No");
	}
	
	return 0;
}