#include <bits/stdc++.h>
using namespace std;

struct node{
    int sz;
    list<int> edge;
    node(){sz=1;};
};
bool check(int r,int c,int N,int M){
    if(0<=r&&r<N)if(0<=c&&c<M)return true;
    return false;
}
int dir4[]={-1,0,1,0,-1};
int dir8[]={0,-1,-1,0,1,-1,1,1,0};
#define mp make_pair
int main() {
    int N,M;cin>>N>>M;N+=2,M+=2;
    vector<string> grid(N);
    using VB=vector<bool>;
    using VVB=vector<VB>;
    VVB used(N,VB(M,false));
    vector<node> tree(1);tree[0].sz=0;
    for(int i = 0; i < M; i++)grid[0]+='.',grid[N-1]+='.';
    for(int i=1;i<N;i++){
        cin>>grid[i];
        grid[i]="."+grid[i]+".";
    }
    int D=0;
    std::function<void(int,int,int)> dfs=[&](int r,int c,int now){
        D++;
        used[r][c]=true;
        stack<pair<int,int>> W;
        vector<pair<int,int>> X;
        W.push(mp(r,c));
        while(W.empty()==false){
            r=W.top().first;c=W.top().second;W.pop();

            for(int i = 0; i < 4; i++){
                int nr=r+dir4[i],nc=c+dir4[i+1];
                if(check(nr,nc,N,M)&&used[nr][nc]==false){
                    used[nr][nc]=true;
                    if(grid[nr][nc]=='.')W.push(mp(nr,nc));
                    else X.push_back(mp(nr,nc));
                }
            }
        }
        for(auto& it : X){
            r=it.first,c=it.second;
            used[r][c]=false;
        }
        for(auto& it : X){
            r=it.first,c=it.second;
            if(used[r][c]==false){
                tree[now].edge.push_back(tree.size());
                tree.push_back(node());
                W.push(mp(r,c));
                used[r][c]=true;
                while(W.empty()==false){

                    r=W.top().first;c=W.top().second;W.pop();
                    grid[r][c]='0'+D;
                    for(int i = 0; i < 8; i++){
                        int nr=r+dir8[i],nc=c+dir8[i+1];
                        if(check(nr,nc,N,M)&&used[nr][nc]==false&&grid[nr][nc]=='x'){
                            tree.back().sz++;
                            used[nr][nc]=true;
                            W.push(mp(nr,nc));
                        }
                    }
                }
                for(int i = 0; i < 4; i++){
                    int nr=r+dir4[i],nc=c+dir4[i+1];
                    if(check(nr,nc,N,M)&&used[nr][nc]==false){
                        dfs(nr,nc,tree.size()-1);
                    }
                }
            }
        }
        D--;
    };
    dfs(0,0,0);

    int Z=tree.size();
    vector<pair<int,int>> dp(Z,mp(0,0));
    std::function<void(int)> dfs2=[&](int v){
        dp[v].first=tree[v].sz;
        dp[v].second=0;
        for(auto& u : tree[v].edge){
            dfs2(u);
            dp[v].first+=dp[u].second;
            dp[v].second+=max(dp[u].first,dp[u].second);
        }
    };
    //for(auto& it : grid){cout << it << endl;}
    dfs2(0);
    cout<<max(dp[0].first,dp[0].second)<<endl;
    return 0;
}