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)

n = gets.chomp!.to_i
s = gets.chomp!.to_s
#n = 6
#s = "abcabc"
ls = s.split("")
if n%2 == 0
  r = n / 2 -1
  second = []
  for i in 0..r do
    second << ls[i]
  end
  #p second
  #p ls
  third = []
  for j in r+1..n-1 do
    third << ls[j]
  end
#p second
#p third
if third == second
  print("Yes\n")
else
  print("No\n")
end

else
  print("No\n")
end