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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
class P{
  static void Main(){
    int n =int.Parse(Console.ReadLine());
    var s = Console.ReadLine();
    int count=0;
    if(n%2==0){
      for(int i=0;i<n/2;i++){
        if(s[i]!=s[i+n/2]){count++;}
      }
    }
    else{count++;}
    Console.WriteLine(count==0?"Yes":"No");
  }
}