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>
#include<string.h>

int isK(char s[]){
	int n=strlen(s);
	for(int i=0;i<n/2;i++){
		if(s[i]!=s[n-i-1]){
			return 0;
		}
	}
	return 1;
}

int main(){
	char s[101];
	scanf("%s", s);
	int n=strlen(s);
	char t[50], tt[50];
	strncpy(t, s+0, (n-1)/2);
	strncpy(tt, s+(n+3)/2-1, (n-1)/2);
	
///	printf("s %s t %s tt %s\n", s, t, tt);
	
	int isOK=1;
	if(isK(s)==0) isOK=0;
	if(isK(t)==0) isOK=0;
	if(isK(tt)==0) isOK=0;
	
	if(isOK){
		printf("Yes");
	}else{
		printf("No");
	}
	return 0;
}