#include <bits/stdc++.h>
using namespace std;
ifstream f("gigelajungeacasa.in");
ofstream g("gigelajungeacasa.out");

int v[1002][1002];

struct Punct{
   int i,j;
};

void rezdrum(int x,int y){
    int i=x;
    int j=y;
    v[x][y]=1;
    queue<Punct> c;
    c.push({i,j});
    while(!c.empty()){
        if(v[i-1][j]==0){
            v[i-1][j]=v[i][j]+1;
            c.push({i-1,j});
        }
        if(v[i][j+1]==0){
            v[i][j+1]=v[i][j]+1;
            c.push({i,j+1});
        }
        if(v[i+1][j]==0){
            v[i+1][j]=v[i][j]+1;
            c.push({i+1,j});
        }
        if(v[i][j-1]==0){
            v[i][j-1]=v[i][j]+1;
            c.push({i,j-1});
        }
        if(v[i-1][j+1]==0){
            v[i-1][j+1]=v[i][j]+1;
            c.push({i-1,j+1});
        }
        if(v[i+1][j-1]==0){
            v[i+1][j-1]=v[i][j]+1;
            c.push({i+1,j-1});
        }
        if(v[i+1][j+1]==0){
            v[i+1][j+1]=v[i][j]+1;
            c.push({i+1,j+1});
        }
        if(v[i-1][j-1]==0){
            v[i-1][j-1]=v[i][j]+1;
            c.push({i-1,j-1});
        }
        c.pop();
        i=c.front().i;
        j=c.front().j;
    }
}

int main()
{
    int n,m,k,X1,Y1,x2,y2,x,y,xy,yy,xb,yb;
    f>>n>>m>>k;
    f>>X1>>Y1>>x2>>y2;
    f>>xy>>yy>>xb>>yb;
    for(int i=1;i<=k;++i){
        f>>x>>y;
        v[x][y]=-1;
    }
    v[X1][Y1]=0;
    v[x2][y2]=1;
    v[xy][yy]=v[xb][yb]=-1;
    for(int i=0;i<=n+1;i++)
        v[i][0]=v[i][m+1]=-1;
    for(int j=0;j<=m+1;++j)
        v[0][j]=v[n+1][j]=-1;
    rezdrum(x2,y2);
    g<<v[X1][Y1]-1;
    return 0;
}