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)

#![allow(unused_imports)]
#![allow(dead_code)]

use std::io::{ self, BufRead };
use std::iter::Iterator;
use std::cmp::*;
use std::collections::*;
use std::str;

fn sum(mut x: i64) -> i64 {
    let mut y = 0;
    while x > 0 {
        y += x % 10;
        x /= 10;
    }
    y
}

fn main() {
    let stdin = io::stdin();
    let mut cin = stdin.lock();

    let ss = cin.split(b'\n')
    .map(|s| s.unwrap()).take(3).collect::<Vec<_>>();
    let n = str::from_utf8(&ss[0]).unwrap().parse::<usize>().unwrap();

    let s = &ss[1];
    let t = &ss[2];

    let mut m = 0;
    for i in 0..(n+1) {
        if s[i..] == t[..(n-i)] {
            m = i;
            break;
        }
    }

    let ans = n + m;
    println!("{}", ans);
}