#include <bits/stdc++.h>
#define LL long long
using namespace std;
const int N = 1010;
int n, m;
char g[N][N];
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};

bool f(int x, int y) {
    if (g[x][y] != '.') return false;
    for (int i = 0; i < 4; i++) {
        int nx = x + dx[i], ny = y + dy[i];
        if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
        if (g[nx][ny] == '#') return false;
    }
    return true;
}

int add(int x0, int y0) {
    if (g[x0][y0] != '#') return 0;
    int res = 0;
    bool self_ok = true;
    for (int i = 0; i < 4; i++) {
        int nx = x0 + dx[i], ny = y0 + dy[i];
        if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
        if (g[nx][ny] == '#') {
            self_ok = false;
            break;
        }
    }
    if (self_ok) res++;
    for (int i = 0; i < 4; i++) {
        int nx = x0 + dx[i], ny = y0 + dy[i];
        if (nx < 1 || nx > n || ny < 1 || ny > m) continue;
        if (g[nx][ny] != '.') continue;
        bool origin_bad = false;
        for (int j = 0; j < 4; j++) {
            int nnx = nx + dx[j], nny = ny + dy[j];
            if (nnx < 1 || nnx > n || nny < 1 || nny > m) continue;
            if (g[nnx][nny] == '#' && (nnx != x0 || nny != y0)) {
                origin_bad = true;
                break;
            }
        }
        if (!origin_bad && !f(nx, ny)) {
            res++;
        }
    }
    return res;
}

int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        string s; cin >> s;
        for (int j = 1; j <= m; j++) {
            g[i][j] = s[j-1];
        }
    }
    int base = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (f(i, j)) base++;
        }
    }
    int max_add = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (g[i][j] == '#') {
                max_add = max(max_add, add(i, j));
            }
        }
    }
    cout << base + max_add << endl;
    return 0;
}
//:)
//114514