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 Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program ABC145_B
integer N
character(200)S
logical check
read*,N
read*,S

check=.true.
if(mod(N,2)==1)check=.false.
if(S(1:N/2)/=S(N/2+1:N))check=.false.

if(check)then
  print"(A)","Yes"
else
  print"(A)","No"
endif
end program