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

//#define int long long

typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>inline void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>inline void chmax(T &t,U f){if(t<f)t=f;}

int dy[8]={0,-1,0,1,-1,-1,1,1};
int dx[8]={-1,0,1,0,-1,1,-1,1};

int H,W;
string fld[1111];

int N;
vint nex[111111];
int sz[111111];
vint G[111111];
int paint(int y,int x,char f,char t,int d,int p){
    if(fld[y][x]!=f){
        if(fld[y][x]=='x'){
            nex[p].pb(y*W+x);
            fld[y][x]='y';
        }
        return 0;
    }
    fld[y][x]=t;
    int ret=1;
    rep(i,d){
        int ny=y+dy[i],nx=x+dx[i];
        if(ny<0||ny>=H||nx<0||nx>=W)continue;
        ret+=paint(ny,nx,f,t,d,p);
    }
    return ret;
}

void build(int v,int y,int x){
    rep(i,nex[v].size()){
        int yy=nex[v][i]/W,xx=nex[v][i]%W;
        if(fld[yy][xx]!='y')continue;
        sz[N]=paint(yy,xx,'y','.',8,114514);
        G[v].pb(N);
        N++;
        paint(yy,xx,'.','@',4,N-1);
        build(N-1,yy,xx);
    }
}

int dp0[111111],dp1[111111];
void solve(int v){
    dp0[v]=0;dp1[v]=sz[v];
    rep(i,G[v].size()){
        int to=G[v][i];
        solve(to);
        dp0[v]+=max(dp0[to],dp1[to]);
        dp1[v]+=dp0[to];
    }
}

signed main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    cin>>H>>W;
    H+=2;W+=2;
    reps(i,1,H-1)cin>>fld[i],fld[i]="."+fld[i]+".";
    fld[0]=fld[H-1]=string(W,'.');

    N=1;
    paint(0,0,'.','@',4,0);
    build(0,0,0);
    solve(0);
    cout<<dp0[0]<<endl;
    return 0;
}