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: Accepted)

package main
 
import (
	"fmt"
	"os"
)

func main() {
	var a int
	var b string
	var o string
	fmt.Scan(&a)
	fmt.Scan(&b)
	if a % 2 != 0 {
		fmt.Print("No")
		os.Exit(0)
	}
	f := a / 2
	var lists string
	for i, v := range b{
		lists += string(v)
		if i + 1 == f {
			break
		}
	}
	lists = lists + lists
	if b == lists {
		o = "Yes"
	} else {
		o = "No"
	}
	fmt.Print(o)
}