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++ (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
 
 
using namespace std;
 
void func145b (){
	int n;
	string s;
	cin >> n;
	cin >> s;
	if (s.substr(0, n / 2) == s.substr(n / 2)) cout << "Yes\n";
	else cout << "No\n";
}
 
 
int main()
{
	func145b();
	return 0;	
}