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 (2.11.7) (judge verdict: Accepted)

import io.StdIn.readLine


object Main {
  def main(args: Array[String]): Unit = {
    val n = readLine().toInt
    val s = readLine()
    val t = readLine()

    for (i <- (0 to n).reverse) {
      if (s.slice(n - i, n) == t.slice(0, i)) {
        println(2 * n - i)
        return
      }
    }
  }
}