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.to_i
str = gets.split("")

before = []
index1 = 0
index2 = 0

ans = 0

if N%2 == 1
    puts 'No'
else
    (N/2).times do
        before.push(str[index1])
        index1 += 1
    end
    
    (N/2).times do
        if before[index2] == str[index1]
            ans += 1
            index1 += 1
            index2 += 1
        else
            index1 += 1
            index2 += 1
        end
    end
    
    if ans == N/2
        puts 'Yes'
    else
        puts 'No'
    end
end