alee

#include <bits/stdc++.h>

using namespace std;

ifstream fin("alee.in");
ofstream fout("alee.out");

int n, m, X1, Y1, X2, Y2, d[176][176], di[] = {-1, 0, 1, 0}, dj[] = {0, 1, 0, -1};

struct pozitie {
    int i, j;
} q[176 * 176];

void Lee() {
    int st = 1, dr = 0;
    pozitie aux;
    aux.i = X1, aux.j = Y1;
    ++dr;
    q[dr] = aux;
    d[X1][Y1] = 1;
    while (st <= dr) {
        int i = q[st].i, j = q[st].j;
        ++st;
        // i, j
        // i - 1, j + 0
        // i + 0, j + 1
        // i + 1, j + 0
        // i + 0, j - 1
        // d[i][j] - cel mai scurt drum pana la (i, j)
        for (int k = 0; k < 4; ++k) {
            int iv = i + di[k], jv = j + dj[k];
            if (1 <= iv && iv <= n && 1 <= jv && jv <= n) {
                if (d[iv][jv] == 0) {
                    d[iv][jv] = d[i][j] + 1;
                    aux.i = iv, aux.j = jv;
                    q[++dr] = aux;
                }
            }
        }
    }
}

int main() {
    fin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int x, y;
        fin >> x >> y;
        d[x][y] = -1;
    }
    fin >> X1 >> Y1 >> X2 >> Y2;
    Lee();
    fout << d[X2][Y2] << '\n';
    fin.close();
    fout.close();
    return 0;
}