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;

class Program
{
    void Calc()
    {
        var sc = new Scanner();
        int N = sc.NextInt();
        string C = Console.ReadLine();
        string D = Console.ReadLine();
        if (C==D)
        {
            Console.WriteLine(N);
        }
        if (N == 1 && C!=D)
        {
            {
                Console.WriteLine(2);
            }
        }
        if (N != 1 && C != D)
        {
            for (int i = 1; i < N; i++)
            {
                if (D.Substring(0, i) == C.Substring(N - i))
                {
                    Console.WriteLine(2 * N - (i));
                }
            }
        }

    }

    static void Main()
    {
        new Program().Calc();
    }

    class Scanner
    {
        string[] s = new string[0];
        int i = 0;
        char[] cs = new char[] { ' ' };

        public string Next()
        {
            if (i < s.Length) return s[i++];
            s = Console.ReadLine().Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return s[i++];
        }
        public int NextInt() { return int.Parse(Next()); }
        public long NextLong() { return long.Parse(Next()); }
        public double NextDouble() { return double.Parse(Next()); }
    }
}