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.