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 Fortran (GNU Fortran 9.2.1) (judge verdict: Wrong Answer)

program sample
    implicit none
    character(100)::s,t
    integer(8) :: i,j,m,n
    
  
    read(*,*) n
    read(*,*)s
    read(*,*)t
    
    do i=1,n,-1
        if(s(n+1-i:n) .eq. t(1:i))then
            m=2*n-i
            write(*,*) m
            stop
        end if
    enddo
    write(*,*) n
  
    stop
end program sample