Problem:
Score : 200 points

Problem Statement

Given are a positive integer N and a string S of length N consisting of lowercase English letters.

Determine whether the string is a concatenation of two copies of some string.
That is, determine whether there is a string T such that S = T + T.

Constraints

1 \leq N \leq 100

S consists of lowercase English letters.

|S| = N

Input

Input is given from Standard Input in the following format:

N
S

Output

If S is a concatenation of two copies of some string, print Yes; otherwise, print No.

Sample Input 1

6
abcabc

Sample Output 1

Yes

Let T = abc, and S = T + T.

Sample Input 2

6
abcadc

Sample Output 2

No

Sample Input 3

1
z

Sample Output 3

No

Solution in Kotlin (1.3.71) (judge verdict: Wrong Answer)

fun main(args: Array<String>) {
    val regex = Regex(pattern = "^[a-z]+$")
    var result :String = "No"
    val inputN = readLine()?.toInt() ?: 0
    val inputS = readLine()!!

    if(inputN == inputS.length && inputN < 51 && inputN % 2 == 0 && regex.containsMatchIn(inputS)){
        val firstHalf = inputS.substring(0..(inputN / 2 - 1))
        val secondHalf = inputS.substring((inputN / 2)..(inputN - 1))
        if(firstHalf == secondHalf){
            result = "Yes"
        }
    }
    println(result)
}