Problem:
Score : 200 points

Problem Statement

Snuke is interested in strings that satisfy the following conditions:

The length of the string is at least N.

The first N characters equal to the string s.

The last N characters equal to the string t.

Find the length of the shortest string that satisfies the conditions.

Constraints

1≤N≤100

The lengths of s and t are both N.

s and t consist of lowercase English letters.

Input

The input is given from Standard Input in the following format:

N
s
t

Output

Print the length of the shortest string that satisfies the conditions.

Sample Input 1

3
abc
cde

Sample Output 1

5

The shortest string is abcde.

Sample Input 2

1
a
z

Sample Output 2

2

The shortest string is az.

Sample Input 3

4
expr
expr

Sample Output 3

4

The shortest string is expr.

Solution in Scala (2.13.1) (judge verdict: Accepted)

object Main extends App {
  @scala.annotation.tailrec
  def loop(n: Int, s: String, t: String): Int =
    if (n == 0 || s == t) n else loop(n - 1, s.tail, t.init)

  val sc = new java.util.Scanner(System.in)
  val N = sc.nextInt()
  val s, t = sc.next()
  println(N * 2 - loop(N, s, t))
}