#include<fstream>
using namespace std;
short n,m,xi,yi,xf,yf,b[177][177];
short dx[]={-1,0,1,0};
short dy[]={0,1,0,-1};
short q[30625][2];
struct alee{
        short x,y;
};
alee a[15000];

void citire()
{
        ifstream fin("alee.in");
        short i,j,k;
        fin>>n>>m;
        for(k=1;k<=m;k++){
                fin>>a[k].x>>a[k].y;
                b[a[k].x][a[k].y]=-1;
        }
        fin>>xi>>yi>>xf>>yf;
        for(i=1;i<=n;i++)
        {
                for(j=1;j<=n;j++)
                        if(b[i][j]!=-1)
                                b[i][j]=31000;
        }
        b[xi][yi]=0;
}
void afisare()
{
        ofstream fout("alee.out");
        fout<<b[xf][yf]+1;
}
void lee(short c[177][177])
{
 int i,x,y,xx,yy,st=0,dr=0,ok=0;
 q[0][0]=xi;
 q[0][1]=yi;
 while(st<=dr&&ok==0)
 {
         x=q[st][0];
         y=q[st][1];
         for(i=0;i<4;i++)
         {
                 xx=x+dx[i];
                 yy=y+dy[i];
                 if(c[xx][yy]==31000)
                 {
                         c[xx][yy]=c[x][y]+1;
                         dr++;
                         q[dr][0]=xx;
                         q[dr][1]=yy;
                 }
                 if(xx==xf&&yy==yf)
                         ok=1;
         }
         st++;
  }
}
int main()
{

        citire();
        lee(b);
        afisare();
        return 0;
}