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 Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn main() {
    let mut num = String::new();//String;
    let mut s = String::new();
    let mut t = String::new();
    io::stdin().read_line(&mut num);
    io::stdin().read_line(&mut s);
    io::stdin().read_line(&mut t);

    let num = num.trim();
    let s = s.trim();
    let t = t.trim();

    for i in 0..num.parse::<i32>().unwrap() {
        if s[i as usize..s.len()] == t[0..(s.len() - i as usize ) as usize] {
            print!("{}", s.len() + i as usize);
            return;
        }
    }
    print!("{}", s.len() * 2);
}