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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		// 複数行の標準入力
		ArrayList<String> strList = new ArrayList<String>();
		Scanner in = new Scanner(System.in);
		while (in.hasNext()) {
			String buf = in.nextLine();
			strList.add(buf);
		}
		in.close();

		// 入力データの分割
		int strLength = Integer.parseInt(strList.get(0));
		String s = strList.get(1);
		String t = strList.get(2);
		String tmpS = null;
		for (int i = 1; i <= strLength; i++) {
			String tmp = s.substring(strLength - i);
			if (t.startsWith(tmp)) {
				tmpS = s + t.substring(i);
			}
		}
		if (tmpS == null) {
			tmpS = s + t;
		}

		int resultLength = tmpS.length();

		System.out.println(resultLength);
	}
}