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 (gfortran v4.8.4) (judge verdict: Accepted)

program name
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int32):: n,i,overlap
    character(:),allocatable:: s,t

    read*, n
    allocate(character(n):: s,t)
    read*, s
    read*, t

    overlap=0
    do i=n-1,0,-1
        if (s(n-i:n) == t(1:1+i)) then
            print'(i0)', 2*n-(i+1)
            stop
        end if
    end do
    print'(i0)', 2*n
end program name