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>
#include<iostream>
#include<stack>
#include<string>
#include<vector>
#include<queue>
#include<map>
#include<algorithm>
#include<iomanip>
#include<set>
#include<bitset>
#include<cmath>
#include<numeric>
#include<limits>
#include<functional>
#include <bitset>

#define REP(i, m, n) for(int i = (m); i < (n); i++)
#define rep(i,n) REP(i,0,n)
#define NIL -1
using namespace std;
typedef long long ll;
typedef long long int lli;
// static const int MOD = 998244353;
// static const int MAX = 100005;
// static const int ls = 101;
// static const int NMAX = 5005;
// static const lli INFTY = 1000000000000;

// typedef priority_queue<int, greater<int>> RevQ;
int n;
string s;
// lli l, r;
// lli gcd(lli a, lli b) {
//   return b ? gcd(b, a%b) : a;
// }



int main(){
  cin >> n;
  cin >> s;
  if (n % 2 == 1) {
    cout << "No" << endl;
  } else {
    int m = n/2;
    int flag = 0;
    rep(i, m) {
      if (s[i] != s[i + m]) flag = 1;
    }
    if (flag) {
      cout << "No" << endl;
    } else {
      cout << "Yes" << endl;
    }
  }
}