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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

$n = trim(fgets(STDIN));
$s = trim(fgets(STDIN));
$t = trim(fgets(STDIN));
$j = false;

for ($i = 0; $i < $n; $i++) {
    if (substr($s, $i) == substr($t, 0, $n - $i)) {
        echo $n + $i;
        $j = true;
        break;
    }
}
if (!$j) echo $n * 2;