#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
const int N = 1087;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
char g[N][N];
int n, m;
vector<pair<int,int>> h[N*N];
const int inf = N * N;
int dist[N * N];
int id(int x, int y) {
return x * m + y;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int i = 0; i < n; i++)
cin >> g[i];
int a, b, c, d;
cin >> a >> b >> c >> d;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; ++j) {
int u = id(i, j);
if (g[i][j] == '.') {
for (int k = 0; k < 4; ++k) {
int x = i + dx[k];
int y = j + dy[k];
int v = id(x, y);
if (min(x, y) < 0 || x >= n || y >= m)
continue;
if (g[x][y] == '.') {
h[u].emplace_back(0, v);
}
}
} else {
for (int k = 0; k < 4; ++k) {
for (int s = 1; s <= 2; ++s) {
int x = i + dx[k] * s;
int y = j + dy[k] * s;
int v = id(x, y);
if (min(x, y) < 0 || x >= n || y >= m)
continue;
if (g[x][y] == '.') {
h[v].emplace_back(1, u);
h[u].emplace_back(s - 1, v);
} else {
h[u].emplace_back(1, v);
}
}
}
}
}
}
--a, --b, --c, --d;
int s = id(a, b);
int t = id(c, d);
priority_queue<pii, vector<pii>, greater<pii>> pq;
fill_n(dist, n * m, inf);
dist[s] = 0;
pq.emplace(0, s);
while (pq.size()) {
int w, u;
tie(w, u) = pq.top();
pq.pop();
if (w != dist[u])
continue;
for (auto [x, v] : h[u]) {
int nw = w + x;
if (nw < dist[v]) {
dist[v] = nw;
pq.emplace(nw, v);
}
}
}
cout << dist[t] << '\n';
}