#include<bits/stdc++.h>

 using namespace std;

 const int mx[]={,-,,,},my[]={,,,-,};

 const int maxn=;

 int n,m,g[maxn][maxn],vis[maxn][maxn],f[maxn][maxn],sum,cnt,sx,sy,bx,by,flag,ans=0x3f3f3f3f;

 struct node{int x,y,num;};

 int main(){

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

     for(int i=;i<=n;i++)

         for(int j=;j<=m;j++){

             scanf("%d",&g[i][j]);

             if(g[i][j]==) sx=i,sy=j;

             else if(g[i][j]==) bx=i,by=j;

             else if(g[i][j]==) sum++;

         }

     queue<node> q; cnt=sum;

     q.push((node){sx,sy,}),vis[sx][sy]=;

     while(!q.empty()){

         node now=q.front(); q.pop();

         for(int i=;i<=;i++){

             int xx=now.x+mx[i],yy=now.y+my[i];

             if(xx>&&xx<=n&&yy>&&yy<=m&&!vis[xx][yy]&&g[xx][yy]!=){

                 if(g[xx][yy]==&&f[xx][yy]==) f[xx][yy]=now.num+,cnt--;

                 if(!cnt) goto end;

                 q.push((node){xx,yy,now.num+}); vis[xx][yy]=;

             }

         }

     }

     end: memset(vis,,sizeof(vis));

     while(!q.empty()) q.pop(); cnt=sum;

     q.push((node){bx,by,}),vis[bx][by]=;

     while(!q.empty()){

         node now=q.front(); q.pop();

         for(int i=;i<=;i++){

             int xx=now.x+mx[i],yy=now.y+my[i];

             if(xx>&&xx<=n&&yy>&&yy<=m&&!vis[xx][yy]&&g[xx][yy]!=){

                 if(g[xx][yy]==) ans=min(now.num++f[xx][yy],ans),cnt--;

                 if(!cnt) goto print;

                 q.push((node){xx,yy,now.num+}); vis[xx][yy]=;

             }

         }

     }

     print:    printf("%d",ans);

     return ;

 }