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 Scala (2.11.7) (judge verdict: Wrong Answer)

// Main
object Main {
  def main(args:Array[String]) = {
    val sc = new java.util.Scanner(System.in)
    val len = sc.nextInt
    val s = sc.next
    if (len % 2 == 0) {
      println("No")
      System.exit(0)
    }
    val s1 = s.substring(0,len/2)
    val s2 = s.substring(len/2, len)
    if (s1 == s2) {
      println("Yes")
    } else {
      println("No")
    }
  }
}