#include <fstream>
#include <algorithm>
#include <cstring>
#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <map>
#include <deque>
using namespace std;

ifstream in { "input.in" };
ofstream out { "output.out" };

using Pair = pair<int, int>;

const int dx[] = { -1, 0, 1, 0 };
const int dy[] = { 0, 1, 0, -1 };

int n;
Pair start, stop;
bool a[200][200];

void citeste() {
    int m;
    in >> n >> m;

    while (m--) {
        int i, j;
        in >> i >> j;

        a[i][j] = true;
    }

    in >> start.first >> start.second >> stop.first >> stop.second;
    --start.first;
    --start.second;
    --stop.first;
    --stop.second;
}

int Lee() {
    int d[200][200] = {};
    d[start.first][start.second] = 1;
    a[start.first][start.second] = true;

    queue<Pair> q;
    q.push(start);
    while (!q.empty()) {
        Pair p = q.front();
        q.pop();

        for (int k { 0 }; k < 4; ++k) {
            int i { p.first + dx[k] };
            int j { p.second + dy[k] };

            if (i >= 0 && j >= 0 && i < n && j < n && !a[i][j] && !d[i][j]) {
                d[i][j] = d[p.first][p.second] + 1;
                if (i == stop.first && j == stop.second)
                    return d[i][j];

                q.emplace(i, j);
            }
        }
    }

    return d[stop.first][stop.second];
}

int main() {

    citeste();
    out << Lee();
}