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
# A, B, C = gets.chomp.split.map(&:to_i)
S = gets.chomp.chars

def solve
  if N % 2 != 0
    print "No\n"
    return
  end
  # Now, N is odd

  ans = true
  0.upto(N/2 - 1).each do |i|
    if (S[i] != S[i + N/2])
      ans = false
      break
    end
  end

  if ans
    print "Yes\n"
  else
    print "No\n"
  end
end

solve