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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
	input = input.split("\n");
	tmp = input[1].split(" ");
	var N = parseInt(input[0], 10);
	var n = N / 2
	var S = input[1]
	if (N === 1) {
	  console.log('No');
	} else {
	  var str = [];
    for (var i = 0; i < S.length / n; i++) {
      str.push(S.substr(i * n, n));
  }
	 // console.log(str);
	  if (str[0] === str[1]){
	    console.log('Yes');
	  } else {
	    console.log('No')
	  }
	}
}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));