#include //#include using namespace std; //using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } const int dx[] = { 1,0,-1,0,1,1,-1,-1 }; const int dy[] = { 0,-1,0,1,1,-1,1,-1 }; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); cout << 2 << endl; int h, w; cin >> h >> w; vectors(h); rep(i, h)cin >> s[i]; auto bfs = [&]()->bool { vector> d(h, vector(w, INF)); queue> q; q.emplace(1, 1); d[1][1] = 0; while (!q.empty()) { int x = q.front().first; int y = q.front().second; q.pop(); rep(i, 8) { int nx = x + dx[i]; int ny = y + dy[i]; if ((nx <= 0) || (ny <= 0) || (nx >= h - 1) || (ny >= w - 1))continue; bool chk = true; rep2(j, -1, 2)rep2(k, -1, 2) { int nnx = nx + j; int nny = ny + k; if ('#' == s[nnx][nny])chk = false; } if (!chk)continue; if (chmin(d[nx][ny], d[x][y] + 1)) q.emplace(nx, ny); } } return INF != d[h - 2][w - 2]; }; // 0 if (!bfs()) { cout << 0 << endl; return 0; } int cnt = 0; rep(i, h)rep(j, w) { if (max(i, j) <= 2)continue; if (max(h - 1 - i, w - 1 - j) <= 2)continue; if ('#' == s[i][j])continue; s[i][j] = '#'; if (!bfs()) { cout << 1 << endl; return 0; } s[i][j] = '.'; } cout << 2 << endl; return 0; }