1 #include<iostream>
2 #include<cstdio>
3 #include<queue>
4 #include<cstring>
5 using namespace std;
6 const int N=21;
7 struct node{
8 int x,y,step;
9 }now,nxt;
10 queue<node>q;
11 int n,m;
12 int a[N][N];
13 int xd[4]={-1,0,1,0};
14 int yd[4]={0,1,0,-1};
15 bool vis[N][N];
16 int sx,sy,ex,ey;
17 void bfs()
18 {
19 if(sx==ex&&sy==ey)
20 {
21 cout<<"0"<<endl;
22 return ;
23 }
24 while(!q.empty())q.pop();
25 now.x=sx;now.y=sy;now.step=0;
26 vis[sx][sy]=true;
27 q.push(now);
28 while(!q.empty())
29 {
30 now=q.front();q.pop();
31 for(int i=0;i<4;i++)
32 {
33 int xx=now.x+xd[i];
34 int yy=now.y+yd[i];
35 if(xx>=1&&xx<=n&&yy>=1&&yy<=m&&!vis[xx][yy]&&a[xx][yy])
36 {
37 if(xx==ex&&yy==ey)
38 {
39 cout<<now.step+1<<endl;
40 return ;
41 }
42 nxt.x=xx;
43 nxt.y=yy;
44 nxt.step=now.step+1;
45 vis[nxt.x][nxt.y]=true;
46 q.push(nxt);
47 }
48 }
49 }
50 printf("-1\n");
51 }
52 int main()
53 {
54 while(scanf("%d%d",&n,&m)!=EOF)
55 {
56 if(!n) return 0;
57 memset(vis,0,sizeof(vis));
58 memset(a,0,sizeof(a));
59 for(int i=1;i<=n;i++)
60 for(int j=1;j<=m;j++)
61 {
62 char ch;
63 cin>>ch;
64 if(ch=='#') continue;
65 a[i][j]=1;
66 if(ch=='@') { ex=i; ey=j;}
67 else if(ch=='*') { sx=i; sy=j;}
68 }
69 bfs();
70 }
71 }
