#include<stdio.h>
#include<iostream>
#include<stdlib.h>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<queue>
#include<list>
#include<algorithm>
using namespace std;

#define ll long long
int D[1000][1000];
int edge[1000][1000][4];
int edge2[1000][1000];

int main( void )
{
	FILE *in = fopen( "wire.in", "r" );

	int T;
	for( int C = 0;; C ++ ){
		int N, S;
		fscanf( in, "%d%d", &N, &S );
		if( N == 0 && S == 0 )
			break;
		set< int > xs, ys;
		vector< int > x0s;
		vector< int > y0s;
		vector< int > x1s;
		vector< int > y1s;
		for( int i = 0; i < N; i ++ ){
			int x0, y0, x1, y1;
			fscanf( in, "%d%d%d%d", &x0, &y0, &x1, &y1 );
			xs.insert( x0 );
			xs.insert( x0 + 1 );
			xs.insert( x0 - 1 );
			xs.insert( x1 );
			xs.insert( x1 + 1 );
			xs.insert( x1 - 1 );
			ys.insert( y0 );
			ys.insert( y0 + 1 );
			ys.insert( y0 - 1 );
			ys.insert( y1 );
			ys.insert( y1 + 1 );
			ys.insert( y1 - 1 );
			x0s.push_back( x0 );
			y0s.push_back( y0 );
			x1s.push_back( x1 );
			y1s.push_back( y1 );
		}
		xs.insert( 0 );
		xs.insert( S - 1 );
		ys.insert( 0 );
		ys.insert( S - 1 );
		int sx, sy, ex, ey;
		fscanf( in, "%d%d%d%d", &sx, &sy, &ex, &ey );
		xs.insert( sx );
		ys.insert( sy );
		xs.insert( ex );
		ys.insert( ey );

		map< int, int > xmap, ymap;
		int X = 0, Y = 0;
		for( set<int>::iterator it = xs.begin(); it != xs.end(); it ++ ){
			if( 0 <= *it && *it < S )
				xmap[*it] = X ++;
		}
		for( set<int>::iterator it = ys.begin(); it != ys.end(); it ++ ){
			if( 0 <= *it && *it < S )
				ymap[*it] = Y ++;
		}

		sx = xmap[sx];
		sy = ymap[sy];
		ex = xmap[ex];
		ey = ymap[ey];

		for( int i = 0; i < N; i ++ ){
			x0s[i] = xmap[x0s[i]];
			y0s[i] = ymap[y0s[i]];
			x1s[i] = xmap[x1s[i]];
			y1s[i] = ymap[y1s[i]];
		}

		for( int i = 0; i < X; i ++ ){
		for( int j = 0; j < Y; j ++ ){
			D[i][j] = -1;
			edge[i][j][0] = 0;
			edge[i][j][1] = 0;
			edge[i][j][2] = 0;
			edge[i][j][3] = 0;
			edge2[i][j] = 0;
		}}
		for( int i = 0; i < N; i ++ ){
			int y0 = min( y0s[i], y1s[i] );
			int y1 = max( y0s[i], y1s[i] );
			int x0 = min( x0s[i], x1s[i] );
			int x1 = max( x0s[i], x1s[i] );
			if( x0 == x1 ){
				for( int i = y0; i < y1; i ++ ){
					edge[x1][i][1] = 1;
					edge[x1][i+1][3] = 1;
					edge2[x1][i] = 1;
					edge2[x1][i+1] = 1;
				}
			}
			else{
				for( int i = x0; i < x1; i ++ ){
					edge[i]  [y1][0] = 1;
					edge[i+1][y1][2] = 1;
					edge2[i]  [y1] = 1;
					edge2[i+1][y1] = 1;
				}
			}
		}

		priority_queue< pair<int,pair<int,int> > > wl;
		wl.push( pair<int,pair<int,int> >( -edge2[sx][sy], pair<int,int>(sx,sy) ) );
		while( !wl.empty() ){
			int d = - wl.top().first;
			int x = wl.top().second.first;
			int y = wl.top().second.second;
			wl.pop();
			if( D[x][y] >= 0 )
				continue;
			D[x][y] = d;
			if( x == ex && y == ey )
				break;
			int xx, yy;
			// 0
			xx = x + 1, yy = y + 0;
			if( edge[x][y][0] == 0 && 0 <= xx && xx < X && 0 <= yy && yy < Y && D[xx][yy] < 0 ){
				int d2 = d + edge2[xx][yy];
				wl.push( pair<int,pair<int,int> >( -d2, pair<int,int>(xx,yy) ) );
			}
			// 1
			xx = x + 0, yy = y + 1;
			if( edge[x][y][1] == 0 && 0 <= xx && xx < X && 0 <= yy && yy < Y && D[xx][yy] < 0 ){
				int d2 = d + edge2[xx][yy];
				wl.push( pair<int,pair<int,int> >( -d2, pair<int,int>(xx,yy) ) );
			}
			// 2
			xx = x - 1, yy = y + 0;
			if( edge[x][y][2] == 0 && 0 <= xx && xx < X && 0 <= yy && yy < Y && D[xx][yy] < 0 ){
				int d2 = d + edge2[xx][yy];
				wl.push( pair<int,pair<int,int> >( -d2, pair<int,int>(xx,yy) ) );
			}
			// 3
			xx = x + 0, yy = y - 1;
			if( edge[x][y][3] == 0 && 0 <= xx && xx < X && 0 <= yy && yy < Y && D[xx][yy] < 0 ){
				int d2 = d + edge2[xx][yy];
				wl.push( pair<int,pair<int,int> >( -d2, pair<int,int>(xx,yy) ) );
			}
		}
		printf( "%d\n", D[ex][ey] );
	}
	return 0;
}