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>

int main(){
    char s[256];
    scanf("%s", s);
    int len = 0;
    for (int i = 0;; i++) {
        if(s[i] == '\0'){
            len = i;
            break;
        }
    }
    if(len == 3){
        if(s[0] != s[2])printf("No\n");
        return 0;
    }
    for (int i = 0; i <= len / 4; i++) {
        if(s[i] != s[len / 2 - i - 1]){
            printf("No\n");
            return 0;
        }
        if(s[len / 2 + i + 1] != s[len - i -1]){
            printf("No\n");
            return 0;
        }
        if(s[len / 2 + i + 1] != s[i]){
            printf("No\n");
            return 0;
        }
    }
    printf("Yes\n");
}