// -*- coding: utf-8-unix -*-
#![allow(dead_code, unused_imports, unused_macros, unused_variables)]

use std::cmp::{max, min, Ordering, Reverse};
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
use std::fmt::Debug;
use std::io::{self, Read};
use std::str::FromStr;

const INF_I32: i32 = 1_i32 << 30;
const INF_I64: i64 = 1_i64 << 60;
const INF_I128: i128 = 1_i128 << 120;
const INF_USIZE: usize = usize::MAX / 4;

const INF: i64 = INF_I64;
const UINF: usize = INF_USIZE;
const INF128: i128 = INF_I128;

const MOD1: i64 = 1_000_000_007;
const MOD9: i64 = 998_244_353;
const MOD: i64 = MOD9;
const UMOD: usize = MOD as usize;

// =============================================================================
// Input
// =========================================================================
#[allow(dead_code)]
fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

#[allow(dead_code)]
fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

#[allow(dead_code)]
fn read_mat<T: std::str::FromStr>(n: usize) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}
macro_rules! uin {
    ($($x:ident),+ $(,)?) => {
        let values = read_vec::<usize>();
        let mut iter = values.into_iter();
        $(
            let mut $x = iter
                .next()
                .expect("入力の要素数が不足しています");
        )+
    };
}

macro_rules! iin {
    ($($x:ident),+ $(,)?) => {
        let values = read_vec::<i64>();
        let mut iter = values.into_iter();
        $(
            let mut $x = iter
                .next()
                .expect("入力の要素数が不足しています");
        )+
    };
}
macro_rules! cin {
    ($x:ident $(,)?) => {
        let mut $x: Vec<char> = read::<String>().chars().collect();
    };
}
macro_rules! inuv {
    ($x:ident $(,)?) => {
        let mut $x = read_vec::<usize>();
    };
}
macro_rules! iniv {
    ($x:ident $(,)?) => {
        let mut $x = read_vec::<i64>();
    };
}
// =============================================================================
// Output / Debug
// =============================================================================

macro_rules! p {
    () => {
        println!();
    };
    ($value:expr $(,)?) => {
        println!("{}", $value);
    };
    ($fmt:literal, $($arg:tt)*) => {
        println!($fmt, $($arg)*);
    };
}

macro_rules! join {
    ($iter:expr, $separator:expr $(,)?) => {
        ($iter)
            .into_iter()
            .map(|x| x.to_string())
            .collect::<Vec<_>>()
            .join($separator)
    };
}

macro_rules! pv {
    ($iter:expr $(,)?) => {
        println!("{}", join!($iter, " "));
    };
    ($iter:expr, $separator:expr $(,)?) => {
        println!("{}", join!($iter, $separator));
    };
}

macro_rules! yesno {
    ($condition:expr $(,)?) => {
        println!("{}", if $condition { "Yes" } else { "No" });
    };
    ($condition:expr, $yes:expr, $no:expr $(,)?) => {
        println!("{}", if $condition { $yes } else { $no });
    };
}

macro_rules! d {
    ($($value:expr),+ $(,)?) => {
        #[cfg(debug_assertions)]
        {
            eprint!("[{}:{}]", file!(), line!());
            $(
                eprint!(" {} = {:?}", stringify!($value), &$value);
            )+
            eprintln!();
        }
    };
}

// =============================================================================
// Scalar / Vec utilities
// =============================================================================

macro_rules! chmin {
    ($base:expr, $($value:expr),+ $(,)?) => {{
        let mut updated = false;
        $(
            let value = $value;
            if $base > value {
                $base = value;
                updated = true;
            }
        )+
        updated
    }};
}

macro_rules! chmax {
    ($base:expr, $($value:expr),+ $(,)?) => {{
        let mut updated = false;
        $(
            let value = $value;
            if $base < value {
                $base = value;
                updated = true;
            }
        )+
        updated
    }};
}
macro_rules! min {
    // collection: Vec、配列、スライスなど
    ($iter:expr $(,)?) => {{
        ($iter)
            .iter()
            .min()
            .cloned()
            .expect("min! called on an empty iterator")
    }};

    // 複数の値
    ($first:expr, $($rest:expr),+ $(,)?) => {{
        let mut answer = ($first).clone();
        $(
            chmin!(answer, ($rest).clone());
        )+
        answer
    }};
}

macro_rules! max {
    // collection: Vec、配列、スライスなど
    ($iter:expr $(,)?) => {{
        ($iter)
            .iter()
            .max()
            .cloned()
            .expect("max! called on an empty iterator")
    }};

    // 複数の値
    ($first:expr, $($rest:expr),+ $(,)?) => {{
        let mut answer = ($first).clone();
        $(
            chmax!(answer, ($rest).clone());
        )+
        answer
    }};
}

macro_rules! ndvec {
    ($value:expr; $len:expr) => {
        vec![$value; $len]
    };
    ($value:expr; $len:expr, $($rest:expr),+ $(,)?) => {
        vec![ndvec![$value; $($rest),+]; $len]
    };
}

macro_rules! prefix_sum {
    ($values:expr $(,)?) => {{
        let values = &$values;
        let mut prefix = Vec::with_capacity(values.len() + 1);
        prefix.push(Default::default());
        for &value in values.iter() {
            let next = prefix.last().copied().unwrap() + value;
            prefix.push(next);
        }
        prefix
    }};
}

// 数学的な floor(a / b)。b != 0。
macro_rules! div_floor {
    ($a:expr, $b:expr $(,)?) => {{
        let a = $a;
        let b = $b;
        let q = a / b;
        let r = a % b;
        if r != 0 && ((r > 0) != (b > 0)) {
            q - 1
        } else {
            q
        }
    }};
}

// 数学的な ceil(a / b)。b != 0。
macro_rules! div_ceil {
    ($a:expr, $b:expr $(,)?) => {{
        let a = $a;
        let b = $b;
        let q = a / b;
        let r = a % b;
        if r != 0 && ((r > 0) == (b > 0)) {
            q + 1
        } else {
            q
        }
    }};
}

// =============================================================================
// Integer / floating-point binary search
// =============================================================================

// pred(ok) == true, pred(ng) == false を保ち、最後に true 側の境界を返す。
// ok < ng と ok > ng の双方に対応する。
macro_rules! binsearch {
    (ok = $ok:expr, ng = $ng:expr, $pred:expr $(,)?) => {{
        let mut ok = $ok;
        let mut ng = $ng;
        let mut pred = $pred;

        while ok.abs_diff(ng) > 1 {
            let mid = if ok < ng {
                ok + (ng - ok) / 2
            } else {
                ng + (ok - ng) / 2
            };

            if pred(mid) {
                ok = mid;
            } else {
                ng = mid;
            }
        }

        ok
    }};
}

// false ... true の単調列に対し、最初の true を返す。
// ng は false 側の番兵、ok は true 側の番兵。
macro_rules! first_true {
    ($ng:expr, $ok:expr, $pred:expr $(,)?) => {
        binsearch!(ok = $ok, ng = $ng, $pred)
    };
}

// true ... false の単調列に対し、最後の true を返す。
// ok は true 側の番兵、ng は false 側の番兵。
macro_rules! last_true {
    ($ok:expr, $ng:expr, $pred:expr $(,)?) => {
        binsearch!(ok = $ok, ng = $ng, $pred)
    };
}

// 浮動小数点版。回数を明示することで停止条件の曖昧さを避ける。
macro_rules! binsearch_f64 {
    (ok = $ok:expr, ng = $ng:expr, iter = $iter:expr, $pred:expr $(,)?) => {{
        let mut ok = $ok;
        let mut ng = $ng;
        let mut pred = $pred;

        for _ in 0..$iter {
            let mid = (ok + ng) * 0.5;
            if pred(mid) {
                ok = mid;
            } else {
                ng = mid;
            }
        }

        ok
    }};
}

// =============================================================================
// Sorted slice bounds
// =============================================================================

macro_rules! lower_bound {
    ($slice:expr, $value:expr $(,)?) => {{
        let value = $value;
        ($slice).partition_point(|x| x < &value)
    }};
}

macro_rules! upper_bound {
    ($slice:expr, $value:expr $(,)?) => {{
        let value = $value;
        ($slice).partition_point(|x| x <= &value)
    }};
}

// UTIL
macro_rules! neighbors4 {
    ($y:expr, $x:expr, $h:expr, $w:expr $(,)?) => {{
        const DY: [isize; 4] = [-1, 0, 1, 0];
        const DX: [isize; 4] = [0, 1, 0, -1];

        (0..4).filter_map(move |dir| {
            let ny = $y as isize + DY[dir];
            let nx = $x as isize + DX[dir];

            if 0 <= ny && ny < $h as isize && 0 <= nx && nx < $w as isize {
                Some((ny as usize, nx as usize))
            } else {
                None
            }
        })
    }};
}
macro_rules! run_length {
    ($iter:expr $(,)?) => {{
        let mut result = Vec::new();

        for value in $iter {
            match result.last_mut() {
                Some((last, count)) if *last == value => {
                    *count += 1usize;
                }
                _ => {
                    result.push((value, 1usize));
                }
            }
        }

        result
    }};
}
macro_rules! vector_compress {
    ($iter:expr $(,)?) => {{
        let values: Vec<_> = ($iter).into_iter().collect();

        let mut coordinates = values.clone();
        coordinates.sort();
        coordinates.dedup();

        let compressed = values
            .iter()
            .map(|value| coordinates.binary_search(value).unwrap())
            .collect::<Vec<_>>();

        (compressed, coordinates)
    }};
}

// =============================================================================
// Map / Set literals and counters
// =============================================================================

macro_rules! map {
    ($($key:expr => $value:expr),* $(,)?) => {{
        let mut map = ::std::collections::BTreeMap::new();
        $(map.insert($key, $value);)*
        map
    }};
}

macro_rules! set {
    ($($value:expr),* $(,)?) => {{
        let mut set = ::std::collections::BTreeSet::new();
        $(set.insert($value);)*
        set
    }};
}

macro_rules! count_map {
    ($iter:expr $(,)?) => {{
        let mut count = BTreeMap::new();
        for value in $iter {
            *count.entry(value).or_insert(0usize) += 1;
        }
        count
    }};
}

macro_rules! map_add {
    ($map:expr, $key:expr, $delta:expr $(,)?) => {{
        let key = $key;
        let delta = $delta;
        let map = &mut $map;

        *map.entry(key).or_insert(0) += delta;
    }};
}

macro_rules! map_inc {
    ($map:expr, $key:expr $(,)?) => {
        map_add!($map, $key, 1)
    };
}

macro_rules! map_sub {
    ($map:expr, $key:expr, $delta:expr $(,)?) => {{
        let key = $key;
        let delta = $delta;
        let map = &mut $map;

        let remove = match map.get_mut(&key) {
            Some(value) => {
                if *value <= delta {
                    true
                } else {
                    *value -= delta;
                    false
                }
            }
            None => false,
        };

        if remove {
            map.remove(&key);
            true
        } else {
            false
        }
    }};
}

macro_rules! map_dec {
    ($map:expr, $key:expr $(,)?) => {
        map_sub!($map, $key, 1)
    };
}

macro_rules! sum {
    ($iter:expr $(,)?) => {{
        let mut sum = 0;
        for &value in ($iter).iter() {
            sum += value;
        }
        sum
    }};
}

fn grid_01bfs(mat: &Vec<Vec<usize>>, start: (usize, usize)) -> Vec<Vec<usize>> {
    let h = mat.len();
    let w = mat[0].len();
    let mut res = vec![vec![INF as usize; (w) as usize]; (h) as usize];
    let mut q = VecDeque::new();
    q.push_back(start);
    res[start.0][start.1] = 0;
    while !q.is_empty() {
        let v = q.pop_front().unwrap();
        for i in -1..=1 {
            for j in -1..=1 {
                if (i * j as i32).abs() == 1 || (i == 0 && j == 0) {
                    continue;
                }
                if v.0 == 0 && i == -1 {
                    continue;
                }

                if v.0 == h - 1 && i == 1 {
                    continue;
                }

                if v.1 == 0 && j == -1 {
                    continue;
                }

                if v.1 == w - 1 && j == 1 {
                    continue;
                }
                let nv = ((v.0 as i32 + i) as usize, (v.1 as i32 + j) as usize);
                let mut d = 1;
                if mat[nv.0][nv.1] == 1 {
                    d = 1;
                } else {
                    d = 0;
                }
                if (res[nv.0][nv.1] > res[v.0][v.1] + d) {
                    res[nv.0][nv.1] = res[v.0][v.1] + d;
                    if d == 0 {
                        q.push_front(nv);
                    } else {
                        q.push_back(nv);
                    }
                }
            }
        }
    }

    return res;
}

fn grid_bfs(mat: &Vec<Vec<usize>>, start: (usize, usize)) -> Vec<Vec<usize>> {
    let h = mat.len();
    let w = mat[0].len();
    let mut res = vec![vec![INF as usize; (w) as usize]; (h) as usize];
    let mut q = VecDeque::new();
    q.push_back(start);
    res[start.0][start.1] = 0;
    while !q.is_empty() {
        let v = q.pop_front().unwrap();
        for i in -1..=1 {
            for j in -1..=1 {
                if (i * j as i32).abs() == 1 || (i == 0 && j == 0) {
                    continue;
                }
                if v.0 == 0 && i == -1 {
                    continue;
                }

                if v.0 == h - 1 && i == 1 {
                    continue;
                }

                if v.1 == 0 && j == -1 {
                    continue;
                }

                if v.1 == w - 1 && j == 1 {
                    continue;
                }
                let nv = ((v.0 as i32 + i) as usize, (v.1 as i32 + j) as usize);
                let mut d = 1;
                if mat[nv.0][nv.1] == 1 {
                    continue;
                } else {
                    d = 1;
                }
                if res[nv.0][nv.1] > res[v.0][v.1] + d {
                    res[nv.0][nv.1] = res[v.0][v.1] + d;
                    if d == 0 {
                        q.push_front(nv);
                    } else {
                        q.push_back(nv);
                    }
                }
            }
        }
    }

    return res;
}

fn main() {
    uin!(h, w);
    let mut grid = vec![vec![0; w]; h];
    uin!(a, b);
    uin!(r1, c1, r2, c2);
    uin!(p, q);
    let mut d1 = grid_bfs(&grid, (a - 1, b - 1));
    let mut d2 = grid_bfs(&grid, (p - 1, q - 1));
    let mut res = UINF;
    for i in r1 - 1..r2 {
        for j in c1 - 1..c2 {
            res = min(res, d1[i][j] + d2[i][j] + d1[p - 1][q - 1]);
        }
    }
    p!(res);
}