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 (1.42.0) (judge verdict: Accepted)

use std::io::{stdin, BufRead};
fn main() {
    let stdin = stdin();
    let stdinlock = stdin.lock();
    let mut input = stdinlock.lines();
    let n: usize = input
        .next()
        .expect("read")
        .expect("n")
        .parse()
        .expect("parse");
    let s = input.next().expect("line").expect("s");
    let r = input.next().expect("line").expect("s");
    println!("{}", solve(n, &s, &r,));
}

fn solve(n: usize, s: &str, r: &str) -> usize {
    for drops in 0..n {
        if s[drops..] == r[..n - drops] {
            return n + drops;
        }
    }
    n * 2
    // n * 2
    //     - s.chars()
    //         .zip(r.chars().rev())
    //         .take_while(|(a, b)| a == b)
    //         .count()
}