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: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;

class Program
{
    private static int[] Solve(int N, int x)
    {
        if (2 <= x && x <= N * 2 - 2)
        {
            int[] nums = Enumerable.Range(1, N * 2 - 1).ToArray();
            if (x < N)
            {
                int tmp = nums[0];
                nums[0] = nums[N - 2];
                nums[N - 2] = tmp;
            }
            else if (x > N)
            {
                int tmp = nums[N * 2 - 2];
                nums[N * 2 - 2] = nums[N];
                nums[N] = tmp;
            }
            if (x != N)
            {
                int tmp = nums[x - 1];
                nums[x - 1] = nums[N - 1];
                nums[N - 1] = tmp;
            }
            return nums;
        }
        else
        {
            return null;
        }
    }
    static void Main(string[] args)
    {
        int[] values = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
        int[] result = Solve(values[0], values[1]);
        if (result != null)
        {
            Console.WriteLine("Yes");
            foreach (int n in result) { Console.WriteLine(n); }
        }
        else
        {
            Console.WriteLine("No");
        }
    }
}