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
$n = trim(fgets(STDIN));
$s = trim(fgets(STDIN));
$t = trim(fgets(STDIN));
$ans = "";
if($s===$t){
    $ans=$t;
}else{
    for($i=$n-1;$i>=0;--$i){
        $offsets=substr($s,$i);
        $offsett=substr($t,0,$n-$i);
        if($offsett===$offsets){
            $ans=$s.substr($t,$n-$i);
            break;
        }
    }
    
}
if($ans===""){
    $ans=$s.$t;
}
echo strlen($ans);
?>