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: Accepted)

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        String s = sc.next();
        String t = sc.next();

        System.out.println(subCount(n, s, t));

    }

    private static int subCount(int n,String s, String t) {
        for (int i = 0; i < n; i++) {
            if (s.substring(i, n).equals(t.substring(0, n-i))) {
                return n + i;
            }
        }
        return 2 * n;
    }
}