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 Rust (1.15.1) (judge verdict: Accepted)


fn main() {
    let s : String = read();
    let b_main = is_palindrome(&s);

    let half = (s.len()-1) / 2;
    let s_half  = &s[..half].to_string();
    let b_half = is_palindrome(s_half);
    
    let tmp = (s.len()+3) / 2;
    let s_tmp  = &s[tmp-1..].to_string();
    let b_tmp = is_palindrome(s_tmp);

	if b_main && b_half && b_tmp {
		println!("{}", "Yes");
	} else {
		println!("{}", "No");
	}
}

fn is_palindrome(s : &String) -> bool {
    let l = s.len() / 2;

	let f_half = s.chars().take(l);
	let l_half = s.chars().rev().take(l);

	return f_half.eq(l_half);
}


fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}