#include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<iostream>

 #include<string>

 #include<vector>

 #include<stack>

 #include<bitset>

 #include<cstdlib>

 #include<cmath>

 #include<set>

 #include<list>

 #include<deque>

 #include<map>

 #include<queue>

 #define ll long long

 #define inf 0x3fffffff

 using namespace std;

 struct Node

 {

     int x,y,step;

 };

 queue<Node> q;

 int n,m;

 int a[][];

 int vis[][];

 int d[][]={{,},{,-},{-,},{-,-},{,},{,-},{-,},{-,-}};

 bool check(int x,int y)

 {

     if(x<||x>=n||y<||y>=m)

         return false;

     if(vis[x][y])

         return false;

     return true;

 }

 int bfs(int x1,int y1,int x2,int y2)

 {

     memset(vis,,sizeof(vis));

     q.push( (Node){x1,y1,} );

     vis[x1][y1]=;

     while(!q.empty())

     {

         Node u=q.front();

         q.pop();

         if(u.x==x2&&u.y==y2)//到达目标

         {

             return u.step;

         }

         for(int i=;i<;i++)//遍历八个方向

         {

              int x=u.x+d[i][];

              int y=u.y+d[i][];

              if(check(x,y))//检查边界

              {

                  vis[x][y]=;

                  q.push(Node{x,y,u.step+});//步数加1

              }

         }

     }

     return -;//如果不能吃掉将则输出“-1”

 }

 int main()

 {

     int x1,y1,x2,y2;

     while(~scanf("%d%d%d%d%d%d",&n,&m,&x1,&y1,&x2,&y2))

     {

         memset(vis,,sizeof(vis));

        int ans= bfs(x2,y2,x1,y1);

         printf("%d\n",ans);

     }

     return ;

 }