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: Wrong Answer)

#[allow(unused_imports)]
use proconio::marker::{Bytes, Chars, Usize1};
use proconio::{fastout, input};
#[fastout]
fn main() {
    input! {
        n: usize,
        s: Chars,
        t: Chars,
    }
    if s[0] == t[0] && s[n - 1] == t[n - 1] {
        let mut j = 0;
        while j < n && s[n - 1 - j] == t[n - 1 - j] {
            j += 1;
        }
        if j == n {
            println!("{}", n);
            return;
        }
    }
    for i in 0..n {
        if s[n - 1 - i] == t[i] {
            continue;
        } else {
            println!("{}", n + i + 1);
            return;
        }
    }
}