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: Accepted)

<?php

fscanf(STDIN, '%d', $N);
fscanf(STDIN, '%s', $S);
fscanf(STDIN, '%s', $T);
$result = 2 * $N;
for ($i = 0; $i < $N; $i++) {
	$str = substr($S, $i);
	$str2 = substr($T, 0, $N - $i);
	if ($str === $str2) {
		$result = (2 * $N) - ($N - $i);
		break;
	}
}
echo $result . PHP_EOL;