#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;
 
#include<bits/stdc++.h>
using namespace std;

int dh[]={1,0,-1,0,1,-1,1,-1};
int dw[]={0,1,0,-1,1,-1,-1,1};

int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  
  int h,w;
  cin>>h>>w;
  vector<string> S(h);
  rep(i,h) cin>>S[i];
  
  queue<pair<int,int>> que;
  que.push({0,0});
  vector<vector<int>> dist(h,vector<int>(w,-1));
  dist[0][0]=1;
  while(que.size()){
    auto a=que.front(); que.pop();
    int i=a.first,j=a.second;
    rep(k,8){
      int ni=i+dh[k],nj=j+dw[k];
      if(ni<0 || nj<0 || ni>=h-2 || nj>=w-2) continue;
      bool b=true;
      rep(l,3) rep(m,3){
        if(S[ni+l][nj+m]=='#') b=false;
      }
      if(b==false) continue;
      if(dist[ni][nj]==-1){
        dist[ni][nj]=1;
        que.push({ni,nj});
      }
    }
  }
  if(dist[h-3][w-3]==-1){
    cout<<0<<endl;
    return 0;
  }
  
  rep(i,h) rep(j,w){
    if(i<3 && j<3) continue;
    if(i>=h-3 && j>=w-3) continue;
    if(S[i][j]=='#') continue;
    S[i][j]='#';
    
    queue<pair<int,int>> que1;
  que1.push({0,0});
  vector<vector<int>> dist1(h,vector<int>(w,-1));
  dist1[0][0]=1;
  while(que1.size()){
    auto a=que1.front(); que1.pop();
    int i=a.first,j=a.second;
    rep(k,8){
      int ni=i+dh[k],nj=j+dw[k];
      if(ni<0 || nj<0 || ni>=h-2 || nj>=w-2) continue;
      bool b=true;
      rep(l,3) rep(m,3){
        if(S[ni+l][nj+m]=='#') b=false;
      }
      if(b==false) continue;
      if(dist1[ni][nj]==-1){
        dist1[ni][nj]=1;
        que1.push({ni,nj});
      }
    }
  }
  if(dist1[h-3][w-3]==-1){
    cout<<1<<endl;
    return 0;
  }
  }
  cout<<2<<endl;
  
  return 0;
}