#include <iostream>
#include <cstdio>
#include <queue>

using namespace std;

const int NMAX = 180;

int n, m;
int x1, y1, x2, y2;
int mat[NMAX][NMAX];

int di[] = {-1, 0, 1 , 0};
int dj[] = {0, -1, 0, 1};

int main()
{
    freopen("alee.in", "r", stdin);
    freopen("alee.out", "w", stdout);

    scanf("%d %d", &n, &m);

    for (int i = 1; i <= n; i++) {
        int x, y;
        scanf("%d %d", &x, &y);
        mat[x][y] = -1;
    }

    scanf("%d %d %d %d", &x1, &y1, &x2, &y2);

    for (int i = 0; i <= n + 1; i++) {
        mat[0][i] = mat[i][0] = mat[n + 1][i] = mat[i][n + 1] = -1;
    }

    mat[x1][y1] = 1;


    queue<pair<int, int>> q;
    q.push({x1, y1});

    while (!q.empty()) {
        int i = q.front().first, j = q.front().second;

        for (int d = 0; d < 4; d++) {
            int vi = i + di[d], vj = j + dj[d];

            if (!mat[vi][vj]) {
                mat[vi][vj] = mat[i][j] + 1;
                q.push({vi, vj});
            }
        }

        q.pop();
    }

    printf("%d", mat[x2][y2]);

    return 0;
}