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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

//package B;
//B - Echo
import java.util.Scanner;

public class Main {
    private Main(int n,String st){
        int flag = 0;
        if (n%2==0) {
            for (int i = 0, j = n / 2; i < n / 2; i++, j++) {
                if (st.charAt(i) == st.charAt(j)) {
                    flag++;
                }
            }
        }
        if (flag==n/2&&n%2==0)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        String st = scanner.next();
        Main echObj = new Main(n,st);
    }
}