#![allow(unused_imports)]
#![allow(unused_macros)]
#![allow(non_snake_case)]
use proconio::marker::{Bytes, Chars, Isize1, Usize1};
use proconio::{fastout, input, input_interactive};

#[fastout]
fn main() {
    input! {
        N: usize,
        Q: usize,
        A: [i64; N],
        mut B: [i64; Q],
    }
    B.dedup();
    let B = B;
    // 座標圧縮
    let (A, B) = {
        let mut sorted = A.iter().copied().chain(B.iter().copied()).collect::<Vec<_>>();
        sorted.sort();
        sorted.dedup();
        let mut ret_A = vec![0; N];
        let mut ret_B = vec![0; B.len()];
        for i in 0..N {
            ret_A[i] = sorted.binary_search(&A[i]).unwrap();
        }
        for (i, b) in B.into_iter().enumerate() {
            ret_B[i] = sorted.binary_search(&b).unwrap();
        }
        (ret_A, ret_B)
    };
    debug!(A, B);
    let mut dp = vec![usize::MAX; N];
    dp[0] = 0;
    let pos_per_b = {
        let mut ret = vec![vec![]; 2_010];
        for i in 0..N {
            ret[A[i] as usize].push(i);
        }
        ret
    };
    for b in B {
        let mut new_dp = vec![usize::MAX; N];
        for from in 0..N {
            if dp[from] == usize::MAX {
                continue;
            }
            for to in pos_per_b[b as usize].iter() {
                debug!(from, to, dp[from]);
                chmin!(new_dp[*to], dp[from] + to.abs_diff(from));
            }
        }
        dp = new_dp;
    }
    let ans = dp.iter().min().unwrap();
    println!("{}", ans);
}



#[macro_export]
macro_rules! mat {
    ($($e:expr),*) => { vec![$($e),*] };
    ($($e:expr,)*) => { vec![$($e),*] };
    ($e:expr; $d:expr) => { vec![$e; $d] };
    ($e:expr; $d:expr $(; $ds:expr)+) => { vec![mat![$e $(; $ds)*]; $d] };
}

#[macro_export]
macro_rules! chmin {
    ($a:expr, $b:expr) => {
        if $a > $b {
            $a = $b;
            true
        } else {
            false
        }
    };
}

#[macro_export]
macro_rules! chmax {
    ($a:expr, $b:expr) => {
        if $a < $b {
            $a = $b;
            true
        } else {
            false
        }
    };
}

/// https://maguro.dev/debug-macro/
#[macro_export]
macro_rules! debug {
    ($($a:expr),* $(,)*) => {
        #[cfg(debug_assertions)]
        eprintln!(concat!($("| ", stringify!($a), "={:?} "),*, "|"), $(&$a),*);
    };
}