//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define all(a) (a).begin(), (a).end()
using ll = long long;
const ll INF32 = 2e9;
const ll INF64 = 4e18;

void printYN(bool ok){
    if(ok)cout << "Yes" << endl;
    else cout << "No" << endl;
    return;
}

struct point {
    int w, r, c;
    point(int _w, int _r, int _c){
        w = _w; r = _r; c = _c;
    }
};

int main() {
    int H, W;
    cin >> H >> W;
    int A, B;
    cin >> A >> B;
    A--; B--;
    int R1, C1, R2, C2;
    cin >> R1 >> C1 >> R2 >> C2;
    R1--; C1--; R1--; C2--;
    int P, Q;
    cin >> P >> Q;
    P--; Q--;
    vector<vector<vector<int>>> dist(3, vector<vector<int>>(H, vector<int>(W,INF32)));
    deque<point> dq;
    dq.push_front(point(0, A, B));
    dist[0][A][B] = 0;
    const vector<int> dr = {1, 0, -1, 0},
                      dc = {0, 1, 0, -1};
    while(!dq.empty()){
        auto [w, r, c] = dq.front(); dq.pop_front();
        rep(k, 4){
            int nr = r + dr[k], nc = c+dc[k];
            if(nr<0||H<=nr||nc<0||W<=nc)continue;
            if(dist[w][nr][nc]!=INF32)continue;
            dist[w][nr][nc] = dist[w][r][c]+1;
            dq.push_back(point(w, nr, nc)); 
        }
        if(w==0&&R1<=r&&r<=R2&&C1<=c&&c<=C2){
            if(dist[w+1][r][c]==INF32)dist[w+1][r][c] = dist[w][r][c];
            dq.push_front(point(w+1,r,c));
        }
        if(w==1&&P==r&&Q==c){
            if(dist[w+1][r][c]==INF32)dist[w+1][r][c] = dist[w][r][c];
            dq.push_front(point(w+1,r,c));
        }
    }
    cout << dist[2][A][B] << endl;
    return 0;
}