#include<fstream>
#include<vector>
#define MAX_N 505
using namespace std;
int d[(1<<21) + 2];
vector<int>Q[2];
int N,M, sol;
int A[MAX_N][MAX_N];
int dx[8] = { -1, -1, 0, 1, 1, 1, 0, -1 };
int dy[8] = { 0, 1, 1, 1, 0, -1, -1, -1 };
ifstream f("car.in");
ofstream g("car.out");
inline int code(int i, int j, int dir) { return ((i<<9) + j + (dir<<18)); }
int SI, SJ, FI, FJ;
inline void decode(int stare, int &i, int &j, int &dir)
{
	j = stare&511;
	dir = stare>>18;
	i = (stare>>9)&511;
}
bool expandeaza(int stare)
{
	int i,j,dir;
	int nstare;
	decode(stare, i,j,dir);
	nstare = code(i,j,(dir+7)%8);
	if(d[nstare] > d[stare] + 1)
	{
		d[nstare] = d[stare] + 1;
		Q[d[nstare]&1].push_back(nstare);
	}
	nstare = code(i,j,(dir+1)%8);
	if(d[nstare] > d[stare] + 1)
	{
		d[nstare] = d[stare] + 1;
		Q[d[nstare]&1].push_back(nstare);
	}
	i += dx[dir], j += dy[dir];
	if(i < 1 || j < 1 || i > N || j > M || A[i][j]) return false;	
	nstare = code(i,j,dir);
	if(d[nstare] > d[stare])
	{
		d[nstare] = d[stare];
		Q[d[nstare]&1].push_back(nstare);
	}
	if(i == FI && j == FJ) return true;
	return false;
}
int main()
{
	f>>N>>M>>SI>>SJ>>FI>>FJ;
	int stare, i, j, sol = 0;
	for(i = 1; i <= N; ++i)
		for(j = 1; j <= M; ++j)
			f>>A[i][j];
    for(i = 0; i < (1<<21)+2; ++i) d[i] = 1<<15;
	for( i = 0; i<8; ++i)
	{
		stare = code(SI,SJ,i);
	    Q[0].push_back(stare);
		d[stare] = 0;
	}
	while(Q[0].size() + Q[1].size())
	{
		while(Q[sol&1].size())
		{
			stare = Q[sol&1][ Q[sol&1].size() - 1 ];
			Q[sol&1].pop_back();
			if(expandeaza(stare))
			{
				g<<sol<<"\n";
				return 0;
			}
		}
		++sol;
	}
	g<<"-1\n";
	return 0;
}