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 Ruby (2.3.3) (judge verdict: Accepted)

#coding: utf-8

def str_comp(s,t)
  if s == t then
    return true
  else
    return false
  end
end


def str_count( n , s , t)
  for i in 0..n do
    if str_comp( s[i, n - i], t[0,n - i]) then
      return n - i
    end
  end

  return 0
end


N = STDIN.gets.to_i
s = STDIN.gets
t = STDIN.gets

p 2 * N - str_count(N,s,t)