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>
#include <stdlib.h>
#include <string.h>

int main(){
    int i=0,n;
    char str[101]={};
    scanf("%s",str);
    while (str[i]!='\0') i++;
    n=i;
    for (i=0; i<(n-1)/2; i++) {
        if (str[i]!=str[n-1-i]) {
            printf("No");
            return 0;
        }
    }
    for (i=0; i<(n-1)/4; i++) {
        if (str[i]!=str[(n-1)/2-1-i]) {
            printf("No");
            return 0;
        }
    }
    printf("Yes");
    return 0;
}