#include <iostream>
#include <queue>
#include <vector>
#include <cstring>
using namespace std;

const int di[4] = {-1, 1, 0, 0};
const int dj[4] = {0, 0, -1, 1};



int bfs(int n, int m, vector<string> & v) {
    bool visited[n][m];
    int res = 0;
    memset(visited, false, sizeof visited);
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if(!visited[i][j] and v[i][j] == '.') {
                queue<int> q;
                q.push(i);
                q.push(j);
                res++;

                while(!q.empty()) {
                    int ci = q.front(); q.pop();
                    int cj = q.front(); q.pop();

                    for(int k = 0; k < 4; k++) {
                        int ti = ci + di[k];
                        int tj = cj + dj[k];

                        if(ti >= 0 and ti < n and tj >= 0 and tj < m and !visited[ti][tj] and v[ti][tj] == '.') {
                            q.push(ti);
                            q.push(tj);
                            visited[ti][tj] = true;
                        }
                    }

                }
            }
        }
    }
    return res;
}
int main(){
    ios_base::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    char mat[n][m];

    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];
        }
    }

    int res = 2e9;
    for(int R = 0; R < n; R++) {
        vector<string> v;
        for(int i = 0; i < n; i++) {
            if(i != R) {
                string tmp = "";
                for(int j = 0; j < m; j++) {
                    tmp += mat[i][j];
                }
                v.push_back(tmp);
            }
        }
        res = min(res, bfs(n - 1, m, v));


    }

    for(int C = 0; C < m; C++) {
        vector<string> v;
        for(int i = 0; i < n; i++) {
            string tmp = "";
            for(int j = 0; j < m; j++) {
                if(j != C) {
                    tmp += mat[i][j];
                }
            }
            v.push_back(tmp);


        }
        res = min(res, bfs(n, m - 1, v));
    }

    cout << res << endl;
    return 0;
}