#include <bits/stdc++.h>

using namespace std;

int M[1005][1005];
queue <pair <int, int> > q;
int Ox[] = {-1, 1, 0, 0};
int Oy[] = {0, 0, -1, 1};

bool OK (int i, int j, int n, int m) {return i <= n && j <= m && i >= 1 && j >= 1 && M[i][j] == 0;}

void labirint (int n, int m)
{
    pair <int, int> p;
    while (!q.empty()) {
        for (int i = 0; i < 4; i ++) {
            p = pair <int, int> (q.front().first + Ox[i], q.front().second + Oy[i]);
            if (OK (p.first, p.second, n, m)) q.push(p), M[p.first][p.second] = 1 + M[q.front().first][q.front().second];
        }
        q.pop();
    }
}

int main()
{
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i ++) {
        for (int j = 1; j <= m; j ++) {
            cin >> M[i][j];
            if (M[i][j] == 1) M[i][j] = -1;
        }
    }
    pair <int, int> start, finish;
    cin >> start.first >> start.second >> finish.first >> finish.second;
    q.push(start), M[start.first][start.second] = 1;
    labirint(n, m);
    cout << M[finish.first][finish.second];
    return 0;
}