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 main(void)
{
  int i, j, k, n = 0, ch = 0;
  char kai[100];
  
  scanf("%s" , kai);
  
  for( i = 0; kai[i] != '\0'; i++ ){
    n++;
  }
  //printf("%d\n", n);
  
  for( i = 0; i < n/2; i++ ){
    if( kai[i] != kai[n-i-1] ){
      printf("No\n");
  		return 0;
    }
  }
  
  for( i = 0; i < n/4; i++ ){
    if( kai[i] != kai[n/2 -i-1] ){
      printf("No\n");
  		return 0;
    }
  }
  
  for( i = n/2; i < n/4; i++ ){
    if( kai[i] != kai[n-i-1] ){
      printf("No\n");
  		return 0;
    }
  }
  
  printf("Yes\n");
  return 0;
}