#include <bits/stdc++.h>

using namespace std;
#define local
#ifdef local

template<class T>
void _E(T x) { cerr << x; }

void _E(double x) { cerr << fixed << setprecision(6) << x; }

void _E(string s) { cerr << "\"" << s << "\""; }

template<class A, class B>
void _E(pair<A, B> x) {
    cerr << '(';
    _E(x.first);
    cerr << ", ";
    _E(x.second);
    cerr << ")";
}

template<class T>
void _E(vector<T> x) {
    cerr << "[";
    for (auto it = x.begin(); it != x.end(); ++it) {
        if (it != x.begin()) cerr << ", ";
        _E(*it);
    }
    cerr << "]";
}

void ERR() {}

template<class A, class... B>
void ERR(A x, B... y) {
    _E(x);
    cerr << (sizeof...(y) ? ", " : " ");
    ERR(y...);
}

#define debug(x...) do { cerr << "{ "#x" } -> { "; ERR(x); cerr << "}" << endl; } while(false)
#else
#define debug(...) 114514.1919810
#endif
#define _rep(n, a, b) for (ll n = (a); n <= (b); ++n)
#define _rev(n, a, b) for (ll n = (a); n >= (b); --n)
#define _for(n, a, b) for (ll n = (a); n < (b); ++n)
#define _rof(n, a, b) for (ll n = (a); n > (b); --n)
#define oo 0x3f3f3f3f3f3f3f3f
#define ll long long
#define db long double
#define eps 1e-3
#define bin(x) cerr << bitset<10>(x) << endl
#define what_is(x) cerr << #x << " is " << x << endl
#define met(a, b) memset(a, b, sizeof(a))
#define all(x) x.begin(), x.end()
#define pii pair<ll, ll>
#define pdd pair<db, db>
#define endl "\n"
const ll mod = 1e9 + 7;
const ll maxn = 2e3 + 10;
const db pi = acos(-1.0);

ll qpow(ll a, ll b) {
    ll ret = 1;
    for (; b; a = a * a % mod, b >>= 1) {
        if (b & 1) {
            ret = ret * a % mod;
        }
    }
    return ret;
}

vector<ll> f(maxn), invf(maxn);

ll inv(ll a) {
    return qpow(a, mod - 2);
}

void prework() {
    f[0] = 1;
    _rep(i, 1, maxn - 1) {
        f[i] = f[i - 1] * i % mod;
    }
    invf[maxn - 1] = qpow(f[maxn - 1], mod - 2);
    for (ll i = maxn - 2; i >= 0; i--) {
        invf[i] = invf[i + 1] * (i + 1) % mod;
    }
}

ll C(ll n, ll m) {
    if (n > m || m < 0)return 0;
    if (n == 0 || m == n) return 1;
    ll res = (f[m] * invf[m - n] % mod * invf[n]) % mod;
    return res;
}

char mat[maxn][maxn];
ll dp[maxn][maxn][2];
ll n, m;
pii st, ed;

struct node {
    pii cor;
    int cnt;
};
ll res = -1;
int vis[maxn][maxn];
int d[4][2]{1, 0, 0, 1, -1, 0, 0, -1};

void bfs() {
    deque<node> q;
    q.push_back({st, 0});
    while (!q.empty()) {
        node cur = q.front();
        q.pop_front();
        if (vis[cur.cor.first][cur.cor.second])continue;
        vis[cur.cor.first][cur.cor.second] = 1;
        if (cur.cor == ed) {
            res = cur.cnt;
            return;
        }
        // 先策略1
        _for(i, 0, 4) {
            int xx = cur.cor.first + d[i][1], yy = cur.cor.second + d[i][0];
            if (xx > n || xx < 1 || yy > m || yy < 1 || mat[xx][yy] != '.' || vis[xx][yy])continue;
            q.push_front({make_pair(xx, yy), cur.cnt});
        }
        // 魔法策略
        _rep(i, -2, 2) {
            _rep(j, -2, 2) {
                if (i == 0 && j == 0)continue;
                int xx = cur.cor.first + i, yy = cur.cor.second + j;
                if (xx > n || xx < 1 || yy > m || yy < 1 || mat[xx][yy] != '.' || vis[xx][yy])continue;
                q.push_back({make_pair(xx, yy), cur.cnt + 1});
            }
        }
    }
}

signed main() {
//    ios::sync_with_stdio(false);
//    cin.tie(0);
//    cout.tie(0);
    cin >> n >> m;
    cin >> st.first >> st.second >> ed.first >> ed.second;
    _rep(i, 1, n) {
        scanf("%s", (mat[i] + 1));
    }
    bfs();
    cout << res << endl;

}

Measured memory_bytes: 14140