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: Wrong Answer)

arg = gets
fir = gets.chomp
en = gets.chomp
stock = ""
add = ""
ind = 0
en.reverse.chars do |c|
  if fir[-1 - ind] != c
    add += stock
    if c != fir[-1]
      add += c
      stock = ""
      ind = 0
    else
      stock = c
      ind = 1
    end
  else
    stock += c
    ind += 1
  end
end
if ( add + fir ).length > arg.length 
  puts ( add + fir ).length
else
  puts arg.length
end