#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_set>
#include <vector>
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpii;
typedef vector<pair<ll, ll>> vpll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vc> vvc;
typedef vector<vs> vvs;
typedef vector<vll> vvll;
typedef map<int, int> mii;
typedef set<int> si;
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define arep(i, v) for (auto i : v)
#define irep(it, stl) for (auto it = stl.begin(); it != stl.end(); it++)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\n'
#define STLL(s) strtoll(s.c_str(), NULL, 10)
#define mp(p, q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define fi first
#define se second
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T>
inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline void dump(T& v) {
    irep(i, v) { cout << (*i) << ((i == --v.end()) ? '\n' : ' '); }
}
inline string getline() {
    string s;
    getline(cin, s);
    return s;
}
inline void yn(const bool b) { b ? fin("yes") : fin("no"); }
inline void Yn(const bool b) { b ? fin("Yes") : fin("No"); }
inline void YN(const bool b) { b ? fin("YES") : fin("NO"); }
struct io {
    io() {
        ios::sync_with_stdio(false);
        cin.tie(0);
    }
};
const int INF = INT_MAX;
constexpr ll LLINF = 1LL << 60;
constexpr ll MOD = 1000000007;
constexpr ld EPS = 1e-11;

/* --------------------   ここまでテンプレ   -------------------- */




struct Corr {
    int x;
    int y;
    int depth;
};
deque<Corr> q;

int bfs(int sx, int sy, int gx, int gy, int h, int w, vector<string>& grid) {
    vvi pass(h, vi(w, 0));
    q.push_back({sx, sy, 0});
    vi dx{1, 0,  -1, 0,  -2, -1, 0, 1,  2,  -2, -2, 1,
          2, -2, 2,  -2, -1, 1,  2, -2, -1, 0,  1,  2};
    vi dy{0,  1, 0, -1, -2, -2, -2, -2, -2, -1, -1, -1,
          -1, 0, 0, 1,  1,  1,  1,  2,  2,  2,  2,  2};
    while (!q.empty()) {
        Corr now = q.front();
        // cout << now.x << " " << now.y << " " << now.depth << endl;
        q.pop_front();

        if (pass[now.y][now.x]) continue;
        pass[now.y][now.x] = 1;

        if (now.x == gx && now.y == gy) return now.depth;
        for (int i = 0; i < dx.size(); i++) {
            int nextx = now.x + dx[i];
            int nexty = now.y + dy[i];

            // 次に探索する場所のX座標がはみ出した時
            if (nextx >= w) continue;
            if (nextx < 0) continue;

            // 次に探索する場所のY座標がはみ出した時
            if (nexty >= h) continue;
            if (nexty < 0) continue;

            // 次に探索する場所が既に探索済みの場
            if (grid[nexty][nextx] == '#') continue;
            if(pass[nexty][nextx])continue;

            Corr next = {nextx, nexty, now.depth + (i >= 4)};
            if (i < 4)
                q.push_front(next);
            else
                q.push_back(next);
        }
    }
    return -1;
}

int main() {
    int h, w;
    cin >> h >> w;
    int x, y, gx, gy;
    cin >> y >> x >> gy >> gx;
    y--;
    x--;
    gy--;
    gx--;
    vs v(h);
    rep(i, h) cin >> v[i];
    ll ans = bfs(x, y, gx, gy, h, w, v);
    if (ans != LLINF)
        fin(ans);
    else
        fin(-1);
}


Measured memory_bytes: 10040