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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
	int N;
	string S;

	cin >> N >> S;

	if (N % 2 == 1) {
		cout << "No" << endl;
		return 0;
	}

	for (int i = 0; i < N / 2; i++) {
		if (S[i] != S[i + N / 2]) {
			cout << "No" << endl;
			return 0;
		}
	}

	cout << "Yes" << endl;

	return 0;
}