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 (
  "fmt"
)

func kaibun(str string) bool {
  N := len(str)
  h := int(N / 2)
  for i := 0; i < h; i++ {
    c0, c1 := str[i], str[N-i-1]
    if c0 != c1 {
      return false
    }
  }
  return true
}

func main() {
  var str string
  fmt.Scanf("%s\n", &str)
  
  if !kaibun(str) {
    fmt.Println("No")
    return
  }
  
  if !kaibun(str[:(len(str)-1)/2]) {
    fmt.Println("No")
    return
  }
  
  fmt.Println("Yes")
}