#include <bits/stdc++.h>

int main() {
  using namespace std;
  cin.tie(nullptr)->sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  int si, sj;
  cin >> si >> sj;
  --si, --sj;
  int ti, tj;
  cin >> ti >> tj;
  --ti, --tj;
  vector<string> s(h);
  for (auto&& e : s) cin >> e;
  constexpr array di{1, 0, -1, 0};
  constexpr array dj{0, 1, 0, -1};
  array<array<int, 4>, 6> get_nk;
  get_nk[0] = {1, 2, 3, 4};
  get_nk[1] = {5, 1, 0, 1};
  get_nk[2] = {2, 5, 2, 0};
  get_nk[3] = {0, 3, 5, 3};
  get_nk[4] = {4, 0, 4, 5};
  get_nk[5] = {3, 4, 1, 2};
  vector dist(h, vector<array<int, 6>>(w));
  for (int i = 0; i < h; ++i)
    for (int j = 0; j < w; ++j) dist[i][j].fill(-1);
  vector<tuple<int, int, int>> que{{si, sj, 0}};
  dist[si][sj][0] = 0;
  for (int z = 0; z < int(size(que)); ++z) {
    auto [i, j, k] = que[z];
    if (i == ti and j == tj and k == 0) {
      cout << dist[i][j][k] << '\n';
      exit(0);
    }
    for (int d : {0, 1, 2, 3}) {
      int ni = i + di[d];
      int nj = j + dj[d];
      if (ni < 0 or ni >= h or nj < 0 or nj >= w or s[ni][nj] == '#') continue;
      int nk = get_nk[k][d];
      if (dist[ni][nj][nk] == -1) {
        dist[ni][nj][nk] = dist[i][j][k] + 1;
        que.emplace_back(ni, nj, nk);
      }
    }
  }
  cout << "-1\n";
}