#include <cstdio>
#include <algorithm>
using namespace std;

#define N 52
#define M 16
typedef pair<int,int> P;
char g[M][M];
int w,h;
P id2pos[N]; 
int pos2id[M][M];
int gnum;
P gs[3];
int tbl[N*N*N*N];
int dirs[]={-1,0,1,0,0,-1,0,1};
int qh,qt,q[N*N*N*N];

int operator<(P a, P b) {
  if (a.first!=b.first) return a.first<b.first;
  return a.second<b.second;
}

#define regist(nv)					\
  do {							\
    if (tbl[nv]==-1) {					\
      tbl[nv]=ncost;					\
      q[qt++]=nv;					\
    }							\
  } while(0)
#define check(x,y) \
  (0<=(x)&&(x)<w&&0<=(y)&&(y)<h&&g[(x)][(y)]=='.')

int finished(P rs[]) {
  for (int i=0;i<3;++i) 
    if (rs[i]!=gs[i])
      return 0;
  return 1;
}

int enc(P me, P rs[]) {
  P tmp[3];
  for (int i=0;i<3;++i) tmp[i]=rs[i];
  sort(tmp,tmp+3);

  int res=0;
  res=pos2id[me.first][me.second];
  for (int i=0;i<3;++i) res=res*N+pos2id[tmp[i].first][tmp[i].second];
  return res;
}

void dec(int v, P& me, P rs[]) {
  for (int i=2;i>=0;--i) {
    rs[i]=id2pos[v%N];
    v/=N;
  }
  me=id2pos[v%N];
}

void dump(P me, P rs[]) {
  printf("%d %d\n",me.first,me.second);
  for (int y=0;y<h;++y){
    for (int x=0;x<w;++x){
      char c=g[x][y];
      if (c=='#') putchar('#');
      else if (c=='.') {
	int flag=0;
	if (me.first==x&&me.second==y) {
	  putchar('@');
	  flag=1;
	}
	if (!flag) 
	  for (int i=0;i<3;++i) 
	    if (rs[i].first==x&&rs[i].second==y) {
	      putchar('*');
	      flag=1;
	    }
	if (!flag)
	  for (int i=0;i<3;++i)
	    if (gs[i].first==x&&gs[i].second==y) {
	      putchar('_');
	      flag=1;
	    }
	if (!flag) putchar('.');
	
      }
    }
    puts("");
  }
  puts("--");
}

int solve(int init) {
  memset(tbl,-1,sizeof(tbl));
  qh=qt=0;
  q[qt++]=init;
  tbl[init]=0;
  
  while(qh!=qt) {
    int v=q[qh++];
    int cost=tbl[v];

    P me;
    P rs[3];
    dec(v,me,rs);
    //    dump(me,rs);
    int ncost=cost+1;

    if (finished(rs)) return cost;

    for (int i=0;i<4;++i) {
      int nx=me.first+dirs[2*i];
      int ny=me.second+dirs[2*i+1];
      P nme=make_pair(nx,ny);
      if (!check(nx,ny)) continue;
      int rock=0;
      for (int j=0;j<3;++j) 
	if (nme==rs[j]) {
	  rock=1;
	  int nnx=me.first+dirs[2*i]*2;
	  int nny=me.second+dirs[2*i+1]*2;
	  P nr=make_pair(nnx,nny);
	  if (!check(nnx,nny)) continue;

	  int ok=1;
	  for (int k=0;k<3;++k)
	    if (k!=j&&nr==rs[k])
	      ok=0;
	  if (ok) {
	    rs[j]=nr;
	    int nv=enc(nme,rs);
	    regist(nv);
	    rs[j]=nme;
	  }
	}
      if (!rock) {
	int nv=enc(nme,rs);
	regist(nv);
      }
    }
  }
  return -1;
}

int main() {
  while(scanf("%d%d",&w,&h),w|h) {
    int id=0;
    P start;
    P rs[3];
    int rnum=0;
    gnum=0;

    for (int y=0;y<h;++y)
      for (int x=0;x<w;++x) {
	char c; scanf(" %c",&c);
	g[x][y]=c;
	if (c=='_'||c=='*'||c=='.'||c=='@') {
	  id2pos[id]=P(x,y);
	  pos2id[x][y]=id;
	  ++id;
	  if (c=='@') start=P(x,y);
	  else if (c=='*') rs[rnum++]=P(x,y);
	  else if (c=='_') gs[gnum++]=P(x,y);
	  g[x][y]='.';
	}
      }
    if (id>50) assert(!"too much area!");
    if (rnum!=3) assert(!"less percels");
    if (gnum!=3) assert(!"less goals");

    sort(gs,gs+3);
    printf("%d\n",solve(enc(start,rs)));
  }
}