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>

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

int main(void){
	char s[99]={0};
	scanf("%s",s);
	
	int n=0;
	for(int i=0;s[i]!=0;i++){
		n++;
	}
	
	if(kaibun(s,0,n-1)==1&&kaibun(s,0,(n-1)/2-1)==1&&kaibun(s,(n+3)/2-1,n-1)==1){
		printf("Yes");
	}else{
		printf("No");
	}
	
	
}