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)

=begin
N = gets.to_i               # 単一整数
a = gets.split.map(&:to_i)  # スペースで区切られた複数の整数
a = N.times.map{gets.to_i}  # 縦に並んだ複数の整数。たまにある
s = gets.chomp              # 文字列。chompを付けないと改行文字がついてくる
=end
N = gets.to_i               # 単一整数
s = gets.chomp              # 文字列。chompを付けないと改行文字がついてくる

if N % 2 == 1 or s[0,N/2] != s[N/2,N/2]
  puts "No"
else
  puts "Yes"
end