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 <bits/stdc++.h>
using namespace std;
typedef long long ll;



int main() { // claudio van
  ios_base::sync_with_stdio(false); cin.tie(NULL);
  int n; cin >> n;
  string s; cin >> s;
  string tmp = s.substr(0, n / 2);
  tmp += tmp;
  if (tmp == s and n % 2 == 0) {
    cout << "Yes" << "\n";
  } else {
    cout << "No" << "\n";
  }
  return 0;
}