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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AGC006_A
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.ReadLine();
            var s = Console.ReadLine();
            var t = Console.ReadLine();
            if (s == t)
            {
                Console.WriteLine(s.Length);
                return;
            }
            int N = s.Length;
            int cnt = 0;
            for (int i = 0; i < N; i++)
            {
                if (s[N - i - 1] == t[i])
                {
                    cnt++;
                }
                else break;
            }
            Console.WriteLine(N * 2 - cnt);
        }
    }
}