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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val S = next()
    val N = S.length
    val r1 = 0 .. (N - 1) / 2 - 1
    val r2 = (N + 3) / 2 - 1 .. N - 1
    fun isPal(s: String) =
        (0 until s.length / 2).all { n ->
//System.err.println("n:$n [${s[n]}][${s[s.length - n - 1]}]")
            s[n] == s[s.length - n - 1] }
    val ans = isPal(S) && isPal(S.substring(r1)) && isPal(S.substring(r2))
    println(if (ans) "Yes" else "No")
}

fun next() = readLine()!!
fun nextInt() = Integer.parseInt(next())
fun nextInt(offset: Int = 0) = nextInt() + offset
fun nextLong() = java.lang.Long.parseLong(next())
fun nextLong(offset: Long = 0L) = nextLong() + offset
fun nextDouble() = next().toDouble()
fun listOfString() = next().split(" ")
fun listOfInt() = listOfString().map { Integer.parseInt(it) }
fun listOfInt(offset: Int = 0) = listOfString().map { Integer.parseInt(it) + offset }
fun listOfLong() = listOfString().map { java.lang.Long.parseLong(it) }
fun listOfLong(offset: Long = 0L) = listOfString().map { java.lang.Long.parseLong(it) + offset }
fun listOfDouble() = listOfString().map { it.toDouble() }