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(int argc, char const *argv[]) {
  char a[1000];
  scanf("%s",a);
  int b=strlen(a);
  if (b<7) {
    printf("No\n");
    return 0;
  }
  int c=1;
  for (int i = 0; i < b/2; i++) {
    if (a[i]!=a[b-1-i]) {
      c=0;
    }
  }
  int f=(b+3)/2;
  int k=f;
  for (int i = b-1; i > f; i--) {
    if (a[i]!=a[k-1]) {
      c=0;
    }
    k++;
  }
  if (c==1) {
    printf("Yes");
  }else{
    printf("No");
  }
  return 0;
}