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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php


$N = trim(fgets(STDIN));



$begin = trim(fgets(STDIN));

$end = trim(fgets(STDIN));
$work = $begin . $end;





for ($i = $N; $i > 0; $i--)
{

	
	$cad1 = substr($work, $N -$i,$i);
	$cad2 = substr($work,$N,$i);
	

	
	if($cad1 == $cad2)
	{
		$count =1 ;
		$result = str_replace($cad1.$cad2, $cad1, $work);

		echo $result . "\n";
		die();
	}
	
	
}


echo $work ."\n";
die();