// 入力をscanfにしたときの速度差テスト用
#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define minus(c) memset(c, -1, sizeof c)

const int Max = 110890;
int dx[] = {-1,0,1,0,-1,1,1,-1};
int dy[] = {0,-1,0,1,-1,-1,1,1};
char VisMark = ' ';
char RingMark = 'o';

int N, M;
char G[1010][1010];
int ring_lens[Max];
vector<int> tree[Max]; // to, cost

template<class T> constexpr bool in_range(T y, T x, T H, T W) { return 0<=y&&y<H&&0<=x&&x<W; }

void make_tree() {

  auto get_ring_len = [](int sy, int sx) {
    int ret = 1;
    queue<pair<int, int>> q;
    q.emplace(sy, sx);
    G[sy][sx] = RingMark;
    while(!q.empty()) {
      int y, x; tie(y, x) = q.front(); q.pop();
      rep(i, 8) { // 'x'は8方向
        int ny = y + dy[i], nx = x + dx[i];
        if(!in_range(ny, nx, N, M)) { continue; }
        if(G[ny][nx] != 'x') { continue; }
        G[ny][nx] = RingMark;
        ret ++;
        q.emplace(ny, nx);
      }
    }
    return ret;
  };

  auto get_next_depth_ring = [&](int sy, int sx) {
    vector<tuple<int, int, int>> ret;
    queue<pair<int, int>> q;
    q.emplace(sy, sx);
    G[sy][sx] = VisMark;
    // 次の深さの輪を見つけるために、同じ深さ輪の間の '.' を訪れるBFS
    while(!q.empty()) {
      int y, x; tie(y, x) = q.front(); q.pop();
      rep(i, 4) { // 4方向で輪を跨がずに'.'を消す
        int ny = y + dy[i], nx = x + dx[i];
        if(!in_range(ny, nx, N, M)) { continue; }
        // 同じ深さの輪の間の '.'
        if(G[ny][nx] == '.') {
          G[ny][nx] = VisMark;
          q.emplace(ny, nx);
        }
        // 'x' は輪の要素なので、一つ見つけてあとは塗りつぶす
        if(G[ny][nx] == 'x') {
          ret.emplace_back(ny, nx, get_ring_len(ny, nx));
        }
      }
    }
    return std::move(ret);
  };

  // 同じ深さの木の葉が左から並ぶ (y, x, ノード番号)
  // '.'が連続する領域をノードと捉える
  queue<tuple<int, int, int>> leaves;
  leaves.emplace(0, 0, 0);
  int nextch = 1;
  // BFS木を作る
  while(!leaves.empty()) {
    int ly, lx, leaf; tie(ly, lx, leaf) = leaves.front(); leaves.pop();
    auto ring_nodes = get_next_depth_ring(ly, lx);
    for(auto && e: ring_nodes) {
      int y, x, len; tie(y, x, len) = e;
      tree[leaf].emplace_back(nextch);
      ring_lens[nextch] = len;
      rep(k, 8) { // 8方向で輪を跨ぐ'.'を見つける
        int ny = y + dy[k], nx = x + dx[k];
        if(!in_range(ny, nx, N, M)) { continue; }
        if(G[ny][nx] == '.') {
          leaves.emplace(ny, nx, nextch);
          break;
        }
      }
      nextch++;
    }
  }
}

int dp[Max][2];

int rec(int curr, bool par_used = true) {
  auto& ret = dp[curr][par_used];
  if(ret + 1) { return ret; }
  if(tree[curr].empty()) { return ret = par_used ? 0 : ring_lens[curr]; }
  ret = 0;
  if(par_used) {
    rep(i, tree[curr].size()) { ret += rec(tree[curr][i], false); }
  }
  else {
    int r1 = ring_lens[curr];
    for(auto && e: tree[curr]) { r1 += rec(e, true); }
    int r2 = 0;
    for(auto && e: tree[curr]) { r2 += rec(e, false); }
    ret = max(r1, r2);
  }
  return ret;
}

int main() {
  scanf("%d %d", &N, &M);
  N += 2, M += 2;
  rep(i, M) G[0][i] = '.';
  REP(i, 1, N-1) {
    G[i][0] = '.';
    scanf("%s", G[i]+1);
    G[i][M-1] = '.';
  }
  rep(i, M) G[N-1][i] = '.';
  make_tree();
  minus(dp);
  cout << rec(0) << endl;
  return 0;
}