#include <bits/stdc++.h>
using namespace std;
using LL = long long int;
#define incID(i, l, r) for(int i = (l)    ; i <  (r); ++i)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); --i)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); ++i)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); --i)
#define inc(i, n)  incID(i, 0, n)
#define dec(i, n)  decID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define dec1(i, n) decII(i, 1, n)
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))
#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define FR front()
#define BA back()
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
auto setmin   = [](auto & a, auto b) { return (b <  a ? a = b, true : false); };
auto setmax   = [](auto & a, auto b) { return (b >  a ? a = b, true : false); };
auto setmineq = [](auto & a, auto b) { return (b <= a ? a = b, true : false); };
auto setmaxeq = [](auto & a, auto b) { return (b >= a ? a = b, true : false); };
#define SI(v) static_cast<int>(v.size())
#define RF(e, v) for(auto & e: v)
#define until(e) while(! (e))
#define if_not(e) if(! (e))
#define ef else if
#define UR assert(false)
#define IN(T, ...) T __VA_ARGS__; IN_(__VA_ARGS__);
void IN_() { };
template<typename T, typename ... U> void IN_(T & a, U & ... b) { cin >> a; IN_(b ...); };
template<typename T> void OUT(T && a) { cout << a << endl; }
template<typename T, typename ... U> void OUT(T && a, U && ... b) { cout << a << " "; OUT(b ...); }

// ---- ----

template<typename T> T MV(T v) { return v; }
template<typename T, typename ... U> auto MV(T v, int a, U ... b) { return vector<decltype(MV(v, b ...))>(a, MV(v, b ...)); }

int main() {
	IN(int, h, w, si, sj, gi, gj);
	vector<string> s(h + 2);
	s.FR = string(w + 2, '.');
	inc1(i, h) { IN(string, t); s[i] = "." + t + "."; }
	s.BA = string(w + 2, '.');
	h += 2;
	w += 2;
	
	auto d = MV(h * w + 1, h, w);
	queue<array<int, 3>> q;
	q.push({ si, sj, 0 });
	d[si][sj] = 0;
	until(q.empty()) {
		int i = q.front()[0];
		int j = q.front()[1];
		int t = q.front()[2];
		q.pop();
		inc(k, 4) {
			vector<int> di = { +1,  0, -1,  0, +1, +1, -1, -1, 0 };
			vector<int> dj = {  0, +1,  0, -1, +1, -1, +1, -1, 0 };
			int ii = i + di[k];
			int jj = j + dj[k];
			if_not(inID(ii, 0, h) && inID(jj, 0, w)) { continue; }
			
			if(setmin(d[ii][jj], t + 1)) { q.push({ ii, jj, t + 1 }); }
		}
	}
	OUT(d[gi][gj]);
}