#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60;
const int IINF = (1 << 30) - 1;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int H, W; cin >> H >> W;
    vector<string> S(H); for(int i=0; i<H; i++) cin >> S[i];

    function<bool(vector<string>&, int, int)> isexist = [&](vector<string> &T, int si, int sj){
        if(si==0||sj==0||si==H-1||sj==W-1) return false;

        bool ok = true;
        for(int i=si-1; i<=si+1; i++) for(int j=sj-1; j<=sj+1; j++){
            if(T[i][j]=='#') ok = false;
        }

        return ok;
    };

    function<bool(vector<string>&)> isreach = [&](vector<string> &T){
        int di[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
        int dj[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
        vector<vector<bool>> isvisited(H, vector<bool>(W, false));
        isvisited[1][1] = true;
        queue<pair<int, int>> Q;
        Q.push({1, 1});
        while(!Q.empty()){
            int now_i = Q.front().fi;
            int now_j = Q.front().se;
            Q.pop();

            for(int k=0; k<8; k++){
                int nxt_i = now_i + di[k];
                int nxt_j = now_j + dj[k];
                if(!isexist(T, nxt_i, nxt_j)) continue;
                if(T[nxt_i][nxt_j]=='#') continue;
                if(isvisited[nxt_i][nxt_j]) continue;
                isvisited[nxt_i][nxt_j] = true;
                Q.push({nxt_i, nxt_j});
            }
        }

        if(isvisited[H-2][W-2]) return true;
        else return false;
    };

    //答えが0の場合
    if(!isreach(S)){
        cout << 0 << endl;
        return 0;
    }

    //答えが1の場合
    for(int i=0; i<H; i++) for(int j=0; j<W; j++){
        if((i<=2&&j<=2) || (i>=H-3&&j>=W-3)) continue;
        if(S[i][j]=='#') continue;
        
        vector<string> T = S;
        T[i][j] = '#';
        if(!isreach(T)){
            cout << 1 << endl;
            return 0;
        }
    }

    cout << 2 << endl;
    return 0;
}