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: Accepted)

using System.Collections.Generic;
using System.Linq;
using System;
using static System.Console;

class Program
{
  static void Main() => new Program().solve();

  void solve()
  {
    var n = int.Parse(ReadLine());
    var s = ReadLine();
    var t = ReadLine();

    var machCnt = 0;
    for(var i = 0; i < n; i++)
    {
      if(s.Substring(i) == t.Substring(0, n - i))
      {
        machCnt = n - i;
        break;
      }
    }

    var ans = n * 2 - machCnt;
    WriteLine(ans);
  }
}