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(){
	string s;
	int x;
	cin>>x>>s;
	if(s.size()%2==1){
		cout<<"No"<<endl;
		return 0;
	}
	for(int i=0;i<s.size()/2;++i)
		if(s[i]!=s[i+s.size()/2]){
			cout<<"No"<<endl;
			return 0;
		}
	cout<<"Yes"<<endl;
	return 0;
}