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)

n=gets.to_i

s = gets.chomp.chars
t = gets.chomp.chars


k=0
0.upto(n-1){|i|
p [s,t]
    if s==t
        p n+k;exit
    end
    if s[1..-1]==t[0..-2]
        p n+k+1;exit
    end
    s.shift
    t.pop
    k+=1
}
p k