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 Ruby (2.3.3) (judge verdict: Accepted)

def gi; gets.to_i end
def gs; gets.chomp end
def gli; gets.split(' ').map(&:to_i) end
def d(n); Math.log10(n).to_i + 1 end

N = gi
S = gs
NO = 'No'
YES = 'Yes'

if N.even?
  puts S[0...(N / 2)] == S[(N / 2)..-1] ? YES : NO
else
  puts NO
end