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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.math.*;
 
public class Main {
	public static void main(String[] args)throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		int n = Integer.parseInt(br.readLine());
		String s = br.readLine();
		String t = br.readLine();
		for(int i = 0; i < n; i++){
			for(int j = 0; j < n; j++){
				if(i+j==n){
					sb.append(s.substring(0,i)).append(t);
					System.out.println(sb.length());
					return;
				}
				char c1 = t.charAt(j);
				char c2 = s.charAt(i+j);
				if(c1!=c2){
					i+=j;
					break;
				}
				if(j==n-1){
					sb.append(s);
					System.out.println(sb.length());
					return;
				}
			}
		}
		sb.append(s+t);
		System.out.println(sb.length());
	}
}