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: Runtime Error)

function Main(input) {
	input = input.split('\n')
  	const n = input[0]
    const s = input[1]
    if(n % 2 === 1) {
      console.log('No')
    } else {
        let flag = true
    	let l = 0
        let r = n / 2
        while(r < n) {
        	if(s[l] !== s[r]) {
            	console.log("No")
              	flag = false
              	break
            }
          l++
          r++
        }
        if(flag) {
          console.log("Yes")
        }
    }
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));