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
$stdin = trim(fgets(STDIN));
$N = intval($stdin);
$s = trim(fgets(STDIN));
$t = trim(fgets(STDIN));
$s_ar = str_split($s);
$t_ar = str_split($t);
$result_num = 0;

for ($i = 0; $i < $N; $i++) {
    $s_res = array_slice($s_ar, $i);
    $t_res = array_slice($t_ar, 0, $N-$i);
    if ($s_res === $t_res){
     $result_num = $i;
     break;
    }
}

if ($N===1){
    print(2);
}else{
    print($N+$N-$N+$result_num);
}