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 main(){
	char a[100];
	gets(a);
	int n=strlen(a),r=0,flag1=1,flag2=1;
	int b=(n-1)/2,c=(n+3)/2;
	while(b-1>r){
		if(a[r]!=a[b-1])flag1=0;
		b--;
    	r++;
	}
  	while(n>c){
  		if(a[c-1]!=a[n-1])flag2=0;
		n--;
    	c++;
  	}
  	if(flag1==1&&flag2==1)printf("Yes");
  	else printf("No");
	return 0;
}