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) {
		Scanner in = new Scanner(System.in);
		int num = Integer.parseInt(in.nextLine());
		String s = in.nextLine();
		String t = in.nextLine();
		in.close();
		int mth = num;
		boolean mn = true;
		for (int i = 0; i < num; i++) {
            if (!mn) {
				if (s.charAt(i) != t.charAt(i-mth)) {
					mn = false;
					mth = num;
				} else {
					;
				}
			}
            if (mn) {
				if (s.charAt(i) == t.charAt(0)) {
					mth = i;
					mn = true;
				} else {
					;
				}
			}
		}
		System.out.println(num + mth);
	}
}