#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9;
const int dx[4] = {-1, 1, 0, 0};
const int dy[4] = {0, 0, -1, 1};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int n, m;
    cin >> n >> m;

    vector<vector<int> > a(n + 1, vector<int>(m + 1));
    vector<vector<int> > day(n + 1, vector<int>(m + 1, -1));

    queue<pair<int, int> > q;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];

            if (a[i][j] == 0) {
                day[i][j] = 0;
                q.push(make_pair(i, j));
            }
        }
    }

    int u1, v1, u2, v2;
    cin >> u1 >> v1 >> u2 >> v2;

    // BFS đa nguồn tính ngày tan
    while (!q.empty()) {
        pair<int, int> cur = q.front();
        q.pop();

        int x = cur.first;
        int y = cur.second;

        for (int k = 0; k < 4; k++) {
            int nx = x + dx[k];
            int ny = y + dy[k];

            if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
            if (day[nx][ny] != -1) continue;

            day[nx][ny] = day[x][y] + 1;
            q.push(make_pair(nx, ny));
        }
    }

    // Dijkstra minimax
    vector<vector<int> > dist(n + 1, vector<int>(m + 1, INF));

    priority_queue<
        pair<int, pair<int, int> >,
        vector<pair<int, pair<int, int> > >,
        greater<pair<int, pair<int, int> > >
    > pq;

    dist[u1][v1] = day[u1][v1];
    pq.push(make_pair(dist[u1][v1], make_pair(u1, v1)));

    while (!pq.empty()) {
        pair<int, pair<int, int> > cur = pq.top();
        pq.pop();

        int d = cur.first;
        int x = cur.second.first;
        int y = cur.second.second;

        if (d != dist[x][y]) continue;

        if (x == u2 && y == v2) {
            cout << d << '\n';
            return 0;
        }

        for (int k = 0; k < 4; k++) {
            int nx = x + dx[k];
            int ny = y + dy[k];

            if (nx < 1 || nx > n || ny < 1 || ny > m) continue;

            int nd = max(dist[x][y], day[nx][ny]);

            if (nd < dist[nx][ny]) {
                dist[nx][ny] = nd;
                pq.push(make_pair(nd, make_pair(nx, ny)));
            }
        }
    }

    return 0;
}