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 Go (1.6) (judge verdict: Wrong Answer)

package main
 
import (
    "fmt"
)
 
func main() {
		var s, ans string
		var n,l int
		fmt.Scan(&n)
		fmt.Scan(&s)
		
		l = n/2
		if n%2 == 0{
			if s[:l] == s[l:]{
				ans = "YES"
			}else{
				ans = "NO"
			}
		}else{
			ans = "NO"
		}
		fmt.Println(ans)
}