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(){
  char str[100];
  char *start_str = str;
  int len=0;
  scanf("%s",str);
  while(*start_str!='\0'){
    len++;
    start_str++;
  }
  int i;
  //S is palindrome
  for(i=0;i<len/2;i++){
    if(str[i]!=str[len-i-1]){
      printf("No");
      return 0;
    }
  }
  int front = (len-1)/2;
  for(i=0;i<front;i++){
    if(str[i]!=str[front-i-1]){
      printf("No");
      return 0;
    }
  }
  int rear = (len+3)/2;
  for(i=rear;i<len;i++){
    if(str[i-1]!=str[len-(i-rear)-1]){
      printf("No");
      return 0;
    }
  }
  printf("Yes");
  return 0;
}