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: Runtime Error)

package main

import (
  "fmt"
  "os"
  "bufio"
  "strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main(){
  var len int
  var line string
  if sc.Scan(){
    tmp := sc.Text()
    len, _ = strconv.Atoi(tmp)
  }
  if sc.Scan() {
    line = sc.Text()
  }

  if len % 2 != 0 {
    fmt.Println("No")
    os.Exit(0)
  }

  halfLen := len / 2
  for i := 0; i < len; i++ {
    if line[i] != line[i +halfLen] {
      fmt.Println("Yes")
      os.Exit(0)
    }
  }
  fmt.Println("Yes")
  os.Exit(0)
}