//https://codeforces.com/gym/103269/problem/I
#include <bits/stdc++.h>

using namespace std;

int n, m;
vector<string> v;
vector<vector<vector<int>>> l;

void bfs(int index, int x, int y, int dep = 0) {
    l[index][x][y] = dep;
    if(x + 1 < n and l[index][x + 1][y] > dep + 1 and v[x + 1][y] == '.') {
        bfs(index, x + 1, y, dep + 1);
    }
    if(x - 1 >= 0 and l[index][x - 1][y] > dep + 1 and v[x - 1][y] == '.') {
        bfs(index, x - 1, y, dep + 1);
    }
    if(y + 1 < m and l[index][x][y + 1] > dep + 1 and v[x][y + 1] == '.') {
        bfs(index, x, y + 1, dep + 1);
    }
    if(y - 1 >= 0 and l[index][x][y - 1] > dep + 1 and v[x][y - 1] == '.') {
        bfs(index, x, y - 1, dep + 1);
    }
    return;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    v = vector<string>(n);
    for(int i = 0; i < n; i++) {
        cin >> v[i];
    }
    l = vector<vector<vector<int>>>(4, vector<vector<int>>(n, vector<int>(m, INT_MAX)));
    pair<int, int> a1, a2, b1, b2;
    cin >> a1.first >> a1.second;
    cin >> a2.first >> a2.second;
    cin >> b1.first >> b1.second;
    cin >> b2.first >> b2.second;
    bfs(0, a1.first, a1.second);
    bfs(1, a2.first, a2.second);
    bfs(2, b1.first, b1.second);
    bfs(3, b2.first, b2.second);
    int ans = INT_MAX;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if(l[0][i][j] == INT_MAX or l[1][i][j] == INT_MAX or l[2][i][j] == INT_MAX or l[3][i][j] == INT_MAX) {
                continue;
            }
            //cout << i << " " << j << "\n";
            ans = min(ans, l[0][i][j] + l[1][i][j] + l[2][i][j] + l[3][i][j]);
        }
    }
    if(ans == INT_MAX) {
        cout << "IMPOSSIBLE\n";
    } else {
        cout << ans << "\n";
    }
    return 0;
}