#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;#define maxm 10005const int dx[5]={0,-1,0,1,0};const int dy[5]={0,0,1,0,-1};int n,m,quex[maxm],quey[maxm],qued[maxm];char map[25][25];bool if_[25][25];int bfs(){    int sx,sy,h=0,tail=1;    for(int i=1;i<=n;i++)    {        scanf("%s",map[i]+1);        for(int j=1;j<=m;j++)        {            if_[i][j]=true;            if(map[i][j]==‘@‘) sx=i,sy=j;        }    }    quex[0]=sx,quey[0]=sy,qued[0]=0,if_[sx][sy]=false;    while(h<tail)    {        int nowx=quex[h],nowy=quey[h],d=qued[h++];        for(int i=1;i<=4;i++)        {            int x=nowx+dx[i],y=nowy+dy[i],dd=d+1;            if(x>0&&x<=n&&y>0&&y<=m&&(map[x][y]==‘.‘||map[x][y]==‘*‘)&&if_[x][y])            {                if(map[x][y]==‘*‘) return dd;                if_[x][y]=false;                quex[tail]=x,quey[tail]=y,qued[tail++]=dd;            }        }    }    return -1;}int main(){    scanf("%d%d",&n,&m);    while(n!=0&&m!=0) cout<<bfs()<<endl,scanf("%d%d",&n,&m);;    return 0;}