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 C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;

namespace test2 {

    public class Program {

        public static void Main(string[] args) {

            var n = int.Parse(Console.ReadLine());
            var s = Console.ReadLine();

            if(n % 2 == 0) {

                var s1 = s.Substring(0, n / 2);
                var s2 = s.Substring(n / 2, n / 2);

                if(s1 == s2) {

                  Console.WriteLine("Yes");
                  return;

                }

            }

            Console.WriteLine("No");

        }

    }

}