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)

arg = gets
fir = gets.chomp
en = gets.chomp
en.length.times do |i|
  reg = Regexp.new(en[0..(en.length-1-i)] + "$")
  if fir[reg]
    puts fir.length +  i
    break
  end
  if i == (en.length) -1
    puts (fir + en).length
  end
end