#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
//#include <utility>
#include <set>
#include <iostream>
//#include <memory>
#include <string>
#include <vector>
#include <algorithm>
//#include <functional>
#include <sstream>
//#include <deque>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
//#include <cctype>
#include <cstring>
//#include <ctime>
#include <iterator>
#include <bitset>
//#include <numeric>
//#include <list>
//#include <iomanip>

#if __cplusplus >= 201103L
#include <array>
#include <tuple>
#include <initializer_list>
#include <unordered_set>
#include <unordered_map>
#include <forward_list>

#define cauto const auto&
#else

#endif

using namespace std;


namespace{
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}


#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()


#define MOD 1000000007LL
#define EPS 1e-8
static const int INF=1<<24;
int dd[]={1,0,-1,0,1};

VV(char) vv;
vvint vis;
vvint tmp;
int h,w;
bool foo2(int a,int b){
	if(vv[a][b]==' ') return true;
	if(vis[a][b]!=INF) return false;
	if(vv[a][b]=='#'&&tmp[a][b]!=1){
		tmp[a][b]=-1;
		return false;
	}
	vis[a][b]=1;
	bool ret=false;
	rep(i,4){
		ret|=foo2(a+dd[i],b+dd[i+1]);
	}
	return ret;
}
int foo(int c){
	// cout<<a<<" "<<b<<" "<<c<<endl;
	rep(i,h+2){
		rep(j,w+2){
			if(tmp[i][j]==1){
				if(foo2(i,j)) return c;
			}
		}
	}
	rep(i,h+2){
		rep(j,w+2){
			if(tmp[i][j]==1){
				tmp[i][j]=2;
			}
		}
	}
	rep(i,h+2){
		rep(j,w+2){
			if(tmp[i][j]==-1){
				tmp[i][j]=1;
			}
		}
	}
	return foo(c+1);
}

void mainmain(){
	// int w,h;
	while(cin>>w>>h,w||h){
		initvv(vv,h+2,w+2,' ');
		int x,y;
		initvv(vis,h+2,w+2,INF);
		initvv(tmp,h+2,w+2,0);
		reep(i,1,h+1){
			reep(j,1,w+1){
				cin>>vv[i][j];
				if(vv[i][j]=='&'){
					tmp[i][j]=1;
				}
			}
		}
		cout<<foo(0)<<endl;
	}
}



}
main() try{
    mainmain();
}
catch(...){
}