#include using namespace std; //#include //using multiInt = boost::multiprecision::cpp_int; using ll = long long int; using ld = long double; using pii = pair; using pll = pair; template using smaller_queue = priority_queue, greater>; const int MOD_TYPE = 1; const ll MOD = (MOD_TYPE == 1 ? (ll)(1e9 + 7) : 998244353); const int INF = (int)1e9; const ll LINF = (ll)4e18; const ld PI = acos(-1.0); const ld EPS = 1e-11; #define REP(i, m, n) for (ll i = m; i < (ll)(n); ++i) #define rep(i, n) REP(i, 0, n) #define MP make_pair #define MT make_tuple #define YES(n) cout << ((n) ? "YES" : "NO") << endl #define Yes(n) cout << ((n) ? "Yes" : "No") << endl #define Possible(n) cout << ((n) ? "Possible" : "Impossible") << endl #define possible(n) cout << ((n) ? "possible" : "impossible") << endl #define Yay(n) cout << ((n) ? "Yay!" : ":(") << endl #define all(v) v.begin(), v.end() #define NP(v) next_permutation(all(v)) #define dbg(x) cerr << #x << ":" << x << endl; vector Dx = {0, 0, -1, 1, -1, 1, -1, 1, 0}; vector Dy = {1, -1, 0, 0, -1, -1, 1, 1, 0}; template struct dijkstra { static const int MAX_V = 1000010; const T INF_d; dijkstra(T INF_d_ = LINF) : INF_d(INF_d_) {} struct edge { int to; T cost; }; vector E[MAX_V]; T d[MAX_V]; using pt = pair; void add_E(int a, int b, T c, bool undirected = false) { E[a].push_back(edge{b, c}); if (undirected) E[b].push_back(edge{a, c}); } void calc(int s) { priority_queue, greater> que; fill(d, d + MAX_V, INF_d); que.emplace(0LL, s); d[s] = 0; while (!que.empty()) { pt p = que.top(); que.pop(); int v = p.second; if (d[v] < p.first) continue; for (auto &&e : E[v]) { if (d[e.to] > d[v] + e.cost) { d[e.to] = d[v] + e.cost; que.emplace(d[e.to], e.to); } } } } }; int main() { cin.tie(0); ios::sync_with_stdio(false); cout << setprecision(30) << setiosflags(ios::fixed); int r, c; cin >> r >> c; int sr, sc, gr, gc; cin >> sr >> sc >> gr >> gc; char s[1010][1010]; rep(i, r + 2) rep(j, c + 2) { if (i == 0 || i == r + 1 || j == 0 || j == c + 1) s[i][j] = '.'; else cin >> s[i][j]; } r += 2, c += 2; dijkstra ds; rep(i, r) rep(j, c) { if (s[i][j] == '#') continue; if (i + 1 < r && s[i + 1][j]) ds.add_E(i * c + j, (i + 1) * c + j, 1, true); if (j + 1 < c && s[i][j + 1]) ds.add_E(i * c + j, i * c + j + 1, 1, true); } ds.calc(sr * c + sc); cout << ds.d[gr * c + gc] << endl; return 0; }