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

if (n%2 == 0)
  s1 = s[0..(n/2-1)]
  s2 = s[(n/2)..(n-1)]
  if s1 == s2
    puts "Yes"
  else
    puts "No"
  end
else
  puts "No"
end