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)

require 'pp'
n = gets.to_i
s = gets.chomp.chars
t = gets.chomp.chars
# p s
# p t
# puts '------------'
size = 2 * n
n.times do |i|
  # p s[i..-1].zip(t[0..(n-i-1)])
  if s[i..-1].zip(t[0..(n-i-1)]).all?{|(a,b)|a==b}
    size = 2 * n - s[i..-1].zip(t[0..(n-i-1)]).size
    break
  end
end
p size

# 5 2 4