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>
typedef long long int lld;

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

int main(void) {
  char s[99];
  int l = 0;
  for (l = 0; l < 99; l++) {
    scanf("%c", &s[l]);
    if (s[l] == '\n') {
      break;
    }
  }
  puts(check(s, l) && check(s, (l - 1) / 2) && check(&s[(l + 1) / 2], (l - 1) / 2) ? "Yes" : "No");
}