#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
queue<pair <int,int> > q;
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 l,c, k,lv,cv;
    q.push({li,ci});
    a[li][ci]=1;
    while(!q.empty()&&a[ls][cs]==0)
    {
        l=q.front().first;
        c=q.front().second;
        q.pop();
        for(k=0;k<4;k++)
        {
            lv=l+dl[k];
            cv=c+dc[k];
            if(Inside(lv,cv)&&a[lv][cv]==0)
            {
                q.push({lv,cv});
                a[lv][cv]=a[l][c]+1;
            }
        }
    }


}
int main()
{
    Citire();
    Lee(li,ci);
    if(a[ls][cs]==0)fout<<-1;
    else fout<<a[ls][cs]-1;
    return 0;
}