#include<iostream>
#include<vector>
#include<set>
#include<queue>
#include<cstring>
#define r first
#define c second
using namespace std;
typedef pair<int, int> Point;
const int BUF = 1005;



int row, col;
char b[BUF][BUF];

void read() {
    cin >> row >> col;

    for (int i = 0; i < row + 2; ++i) {
        for (int j = 0; j < col + 2; ++j) {
            b[i][j] = '.';
        }
    }
    
    for (int i = 1; i <= row; ++i) {
        for (int j = 1; j <= col; ++j) {
            cin >> b[i][j];
        }
    }
    
    row += 2;
    col += 2;
}


bool isInside(int r, int c) {
    return 0 <= r && r < row && 0 <= c && c < col;
}


int traceRing(int r, int c, int curId, int ringId[BUF][BUF]) {

    int ringSize = 0;
    ringId[r][c] = curId;
    
    static int dr[] = {-1, -1, -1, 0, 1, 1,  1,  0};
    static int dc[] = {-1,  0,  1, 1, 1, 0, -1, -1};
    
    for (int i = 0; i < 8; ++i) {
        int nr = r + dr[i];
        int nc = c + dc[i];
        if (isInside(nr, nc) && b[nr][nc] == 'x' && ringId[nr][nc] == -1) {
            ringSize += traceRing(nr, nc, curId, ringId);
        }
    }
    
    return ringSize + 1;
}


void colorArea(int r, int c, int currId, bool visited[BUF][BUF],
               vector< set<int> > &adjRing, int ringId[BUF][BUF]) {
    visited[r][c] = true;

    static int dr[] = {-1, 0, 1, 0};
    static int dc[] = {0, 1, 0, -1};

    for (int i = 0; i < 4; ++i) {
        int nr = r + dr[i];
        int nc = c + dc[i];
        if (!isInside(nr, nc)) continue;
        if (b[nr][nc] == 'x') {
            if (currId != ringId[nr][nc])
                adjRing[currId].insert(ringId[nr][nc]);
        }
        else if (!visited[nr][nc]) {
            colorArea(nr, nc, currId, visited, adjRing, ringId);
        }
    }
}


int doDp(bool preUsed, int curr, vector< vector<int> > &dp,
         vector< set<int> > &adjRing, vector<int> &ringId2size) {
    
    int &ret = dp[preUsed][curr];
    if (ret != -1) return ret;
    
    int A = 0; // use current
    int B = 0; // do not use current
    for (set<int>::iterator it = adjRing[curr].begin(); it != adjRing[curr].end(); ++it) {
        A += doDp(true, *it, dp, adjRing, ringId2size);
        B += doDp(false, *it, dp, adjRing, ringId2size);
    }
    
    return ret = (preUsed ? B : max(A + ringId2size[curr], B));
}


void work() {
    int nRing = 1;
    static int ringId[BUF][BUF];
    memset(ringId, -1, sizeof(ringId));

    vector<int> ringId2size;
    ringId2size.push_back(0);
    
    for (int i = 0; i < row; ++i)
        for (int j = 0; j < col; ++j)
            if (b[i][j] == 'x' && ringId[i][j] == -1) {
                int ringSize = traceRing(i, j, nRing++, ringId);
                ringId2size.push_back(ringSize);
            }
    
    vector< set<int> > adjRing;
    adjRing.assign(nRing, set<int>());
    
    static bool visited[BUF][BUF];
    memset(visited, 0, sizeof(visited));
    
    colorArea(0, 0, 0, visited, adjRing, ringId);
    for (int i = 0; i < row; ++i)
        for (int j = 0; j < col; ++j)
            if (!visited[i][j] && ringId[i][j] != -1) {
                colorArea(i, j, ringId[i][j], visited, adjRing, ringId);
            }

    
    vector< vector<int> > dp(2, vector<int>(nRing, -1));
    cout << doDp(false, 0, dp, adjRing, ringId2size) << endl;
}


int main() {
    read();
    work();
    return 0;
}