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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {

	sc.Scan()
	s := sc.Text()
	mid := len(s) / 2
	sr := s[:mid]
	sl := s[mid+1:]

	if isPalindrome(sr) && isPalindrome(sl) && isPalindrome(s) {
		fmt.Print("Yes")
	} else {
		fmt.Print("No")
	}

}

func isPalindrome(s string) bool {
	len := len(s)
	mid := len / 2

	for i := 0; i <= mid; i++ {
		r := len - i - 1

		if s[i] != s[r] {
			return false
		}

	}

	return true
}