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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

uses crt;
var s:string;
i,n:integer;
begin
        clrscr;
        readln(n);
        readln(s);
        if n mod 2 <> 0 then writeln('No')
        else begin
                for i:=0 to trunc(n/2)-1 do begin
                        if s[i+1]<>s[trunc(n/2)+i+1] then begin
                                writeln('No');
                                exit;
                        end;
                end;
                writeln('Yes');
                exit;
        end;
        readln;
end.