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.awt.geom.*;
import java.io.*;
import java.math.*;
import java.text.*; 
import java.util.*;
import java.util.regex.*;

/*
			  br = new BufferedReader(new FileReader("input.txt"));
			  pw = new PrintWriter(new BufferedWriter(new FileWriter("output.txt")));
			  br = new BufferedReader(new InputStreamReader(System.in));
			  pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
 */

public class Main {
	private static BufferedReader br;
	private static StringTokenizer st;
	private static PrintWriter pw;

	public static void main(String[] args) throws IOException {
		br = new BufferedReader(new InputStreamReader(System.in));
		pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
		//int qq = 1;
		int qq = Integer.MAX_VALUE;
		//int qq = readInt();
		for(int casenum = 1; casenum <= qq; casenum++) {
			int n = readInt();
			String s = readToken();
			String t = readToken();
			int ret = n;
			while(true) {
				String test = s + t.substring(t.length() + n - ret);
				if(test.startsWith(s) && test.endsWith(t)) {
					pw.println(ret);
					break;
				}
				ret++;
			}
		}
		exitImmediately();
	}

	private static void exitImmediately() {
		pw.close();
		System.exit(0);
	}

	private static long readLong() throws IOException {
		return Long.parseLong(readToken());
	}

	private static double readDouble() throws IOException {
		return Double.parseDouble(readToken());
	}

	private static int readInt() throws IOException {
		return Integer.parseInt(readToken());
	}

	private static String readLine() throws IOException  {
		String s = br.readLine();
		if(s == null) {
			exitImmediately();
		}
		st = null;
		return s;
	}

	private static String readToken() throws IOException  {
		while(st == null || !st.hasMoreTokens())  {
			st = new StringTokenizer(readLine().trim());
		}
		return st.nextToken();
	}
}