#include <cstdio>
#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 <complex>
#include <stack>
#include <queue>
#include <cstring>
#include <sstream>
#include <cassert>
using namespace std;
static const double EPS = 1e-5;
typedef long long ll;
typedef pair<int,int> PI;
typedef vector<int> vi;
#define rep(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define mp make_pair
#define pb push_back
#define f first
#define s second

int dx[]={0,1,0,-1},dy[]={1,0,-1,0};

int main(){
  int n,m;
  while(cin>>n>>m,n|m){
    char zu[m][n];
    int sx,sy;
    rep(i,m){
      rep(j,n){
        cin>>zu[i][j];
        if(zu[i][j]=='&')sx=i,sy=j;
      }
    }

    int dp[m][n];
    memset(dp,-1,sizeof(dp));

    queue<PI> Q;
    Q.push(mp(sx,sy));
    dp[sx][sy]=0;
    zu[sx][sy]='.';
    int bury=1;

    while(bury<m*n){
      queue<PI> nQ;
      while(!Q.empty()){
        int cx=Q.front().f,cy=Q.front().s;Q.pop();
        rep(i,4){
          int nx=cx+dx[i],ny=cy+dy[i];
          if(nx<0 || nx>=m || ny<0 || ny>=n || dp[nx][ny]!=-1)continue;
          if(zu[nx][ny]!=zu[cx][cy]){
            dp[nx][ny]=dp[cx][cy]+1;
            ++bury;
            nQ.push(mp(nx,ny));
          }else{
            dp[nx][ny]=dp[cx][cy];
            ++bury;
            Q.push(mp(nx,ny));
          }
        }
      }
      Q=nQ;
    }
/*
    rep(i,m){
      rep(j,n)printf("%2d",dp[i][j]);
      cout<<endl;
    }
*/   
    int ans=dp[0][0];
    rep(i,n){
      ans=min(ans,dp[0][i]);
      ans=min(ans,dp[m-1][i]);
    }
    rep(i,m){
      ans=min(ans,dp[i][0]);
      ans=min(ans,dp[i][n-1]);
    }
    cout<<(1+ans)/2<<endl;
  }
}
      