#include <bits/stdc++.h>
#define N 1005
using namespace std;
ifstream fin("roboti.in");
ofstream fout("roboti.out");
///Lee -864
int a[N][N],n,m;
int li,ci,ls,cs;
int dl[]= {-1,0,1,0};
int dc[]= {0,-1,0,1};
///coada
int lin[N*N],col[N*N];
void Citire()
{
    fin>>n>>m;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++)
        {
            fin>>a[i][j];
            a[i][j]=-a[i][j];

        }
    fin>>li>>ci>>ls>>cs;
}
bool Inside(int i, int j)
{
    return i>=1 && i<=n && j>=1 && j<=m;
}
void Lee(int li, int ci)
{
    int st,dr, lv,cv,k,l,c;
    st=dr=1;
    lin[dr]=li;
    col[dr]=ci;///am pus in coada val init
    a[li][ci]=1;
    while(st<=dr)
    {
        l=lin[st];
        c=col[st++];///extrag din coada varf
        for(k=0; k<4; k++)
        {
            lv=l+dl[k];
            cv=c+dc[k];
            if(Inside(lv,cv)&& a[lv][cv]==0)
            {
                a[lv][cv]=a[l][c]+1;
                dr++;
                lin[dr]=lv;
                col[dr]=cv;
            }
        }
    }
}
int main()
{
    Citire();
    Lee(li,ci);
    if(a[ls][cs]==0)fout<<-1;
    else fout<<a[ls][cs]-1;
    return 0;
}