#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<unordered_map>
#include<array>
#include<map>
#include<bitset>
#include<iomanip>
using namespace std;
typedef long long int llint;
typedef long double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
//ios::sync_with_stdio(false);
//std::cin.tie(0);
//<< setprecision(20)
const int mod=1e9+7;
const llint big=1e15+100;
const long double pai=3.141592653589793238462643383279502884197;
const long double ena=2.71828182845904523536;
const long double eps=1e-7;
template <class T,class U>void mineq(T& a,U b){if(a>b){a=b;}}
template <class T,class U>void maxeq(T& a,U b){if(a<b){a=b;}}
template <class T> void soun(T& ar)
{sort(ar.begin(),ar.end());ar.erase(unique(ar.begin(),ar.end()),ar.end());}
llint gcd(llint a,llint b){if(a%b==0){return b;}else return gcd(b,a%b);}
llint lcm(llint a,llint b){return a/gcd(a,b)*b;}
vector<string>grd;
int n,m;
pair<int,int>solve(int iy,int ix){
	queue<pair<int,int>>que;
	que.push(mp(iy,ix));
	queue<pair<int,int>>xx;
	int ansU=0,ansN=0;
	while(!que.empty()){
		int y=que.front().fir;
		int x=que.front().sec;
		que.pop();
		if(y<0||y>n+1||x<0||x>m+1){continue;}
		if(grd[y][x]=='x'){
			grd[y][x]='o';
			xx.push(mp(y,x));
		}
		if(grd[y][x]!='.'){continue;}
		grd[y][x]='+';
		que.push(mp(y,x+1));
		que.push(mp(y,x-1));
		que.push(mp(y+1,x));
		que.push(mp(y-1,x));
	}
	while(!xx.empty()){
		int y=xx.front().fir;
		int x=xx.front().sec;
		if(y<0||y>n+1||x<0||x>m+1){continue;}
		xx.pop();
		if(grd[y][x]!='o'){continue;}
		int itsiz=0;
		queue<pair<int,int>>wa;
		wa.push(mp(y,x));
		int ny=-1;
		int nx=-1;
		while(!wa.empty()){
			int wy=wa.front().fir;
			int wx=wa.front().sec;
			wa.pop();
			if(wy<0||wy>n+1||wx<0||wx>m+1){continue;}
			if(grd[wy][wx]=='.'){ny=wy;nx=wx;}
			if(grd[wy][wx]!='o'){continue;}
			grd[wy][wx]='H';
			itsiz++;
			wa.push(mp(wy-1,wx-1));
			wa.push(mp(wy-1,wx));
			wa.push(mp(wy-1,wx+1));
			wa.push(mp(wy,wx-1));
			wa.push(mp(wy,wx+1));
			wa.push(mp(wy+1,wx-1));
			wa.push(mp(wy+1,wx));
			wa.push(mp(wy+1,wx+1));
		}
		pair<int,int>ret;
		if(ny!=-1){ret=solve(ny,nx);}
		ret.sec+=itsiz;
		maxeq(ret.sec,ret.fir);
		ansU+=ret.sec;
		ansN+=ret.fir;
	}
	return mp(ansU,ansN);
}
int main(void){
	int i,j;cin>>n>>m;
	grd.res(n+2);
	for(j=0;j<m+2;j++){
		grd[0].pub('.');
		grd[n+1].pub('.');
	}
	for(i=1;i<=n;i++){
		string str;cin>>str;
		str.insert(str.begin(),'.');
		str.pub('.');
		grd[i]=str;
	}
	cout<<solve(0,0).fir<<endl;
	return 0;
}