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++14 (GCC 5.4.1) (judge verdict: Accepted)

#define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstring>
using namespace std;
char s[1010];
int main(){
    scanf("%s", s);
    int n = strlen(s);
    int flag = 1;
    for(int i = 0; i < (n - i - 1); i ++){
        if(s[i] != s[n - i - 1]){
            flag = 0;
            break;
        }
    }
    int temp = n;
    if(flag){
        n = (n - 1) / 2;
        for(int i = 0; i < (n - i - 1); i ++){
            if(s[i] != s[n - i - 1]){
                flag = 0;
                break;
            }
        }
    }
    if(flag){
        n = temp;
        int start = (n + 3) / 2 - 1;
        for(int i = start; i < (n - (i - start) - 1); i ++){
            if(s[i] != s[n - (i - start) - 1]){
                flag = 0;
                break;
            }
        }
    }
    if(flag){
        printf("Yes\n");
    }
    else{
        printf("No\n");
    }
    return 0;
}