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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner scan = new Scanner(System.in);
        int N = scan.nextInt();
        String s = scan.next();
        String t = scan.next();
        
        int i = 0;
        int matchCount = 0;
        while(i < N) {
            String sSub = s.substring(s.length() - i - 1, s.length());
            String tSub = t.substring(0, i + 1);

            if(sSub.equals(tSub)) {
                matchCount = i + 1;
                break;
            }
            i++;
        }
        
        System.out.println(s.length() + t.length() - matchCount);
    }
}