#include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <utility>
#include <cmath>
#include <cassert>
#include <cstdio>

using namespace std;
using namespace placeholders;

using LL = long long;
using ULL = unsigned long long;
using VI = vector< int >;
using VVI = vector< vector< int > >;
using VS = vector< string >;
using SS = stringstream;
using PII = pair< int, int >;
using VPII = vector< pair< int, int > >;
template < typename T = int > using VT = vector< T >;
template < typename T = int > using VVT = vector< vector< T > >;
template < typename T = int > using LIM = numeric_limits< T >;

template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; }
template < typename T > inline ostream& operator<<( ostream &s, const vector< T > &v ){ for ( int i = 0; i < int( v.size() ); ++i ){ s << ( " " + !i ) << v[i]; } return s; }
template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; }
template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); }

#define REP2( i, n ) REP3( i, 0, n )
#define REP3( i, m, n ) for ( int i = ( int )( m ); i < ( int )( n ); ++i )
#define GET_REP( a, b, c, F, ... ) F
#define REP( ... ) GET_REP( __VA_ARGS__, REP3, REP2 )( __VA_ARGS__ )
#define FOR( e, c ) for ( auto &&e : c )
#define ALL( c ) begin( c ), end( c )
#define AALL( a, t ) ( t* )a, ( t* )a + sizeof( a ) / sizeof( t )
#define DRANGE( c, p ) ( c ).begin(), ( c ).begin() + ( p ), ( c ).end()

#define SZ( v ) ( (int)( v ).size() )
#define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() )

template < typename T > inline bool chmin( T &a, const T &b ){ if ( b < a ) { a = b; return true; } return false; }
template < typename T > inline bool chmax( T &a, const T &b ){ if ( a < b ) { a = b; return true; } return false; }

#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define MP make_pair
#define fst first
#define snd second

#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

int N, M;
VS board;

VVI G;
VI sizes;

VVI visited;

constexpr bool inside( const int y, const int x )
{
	return 0 <= y && y < N && 0 <= x && x < M;
}

inline bool throuable( const int y1, const int x1, const int y2, const int x2 )
{
	if ( board[ y2 ][ x2 ] == 'x' )
	{
		return false;
	}

	const auto mmy = minmax( y1, y2 );
	const auto mmx = minmax( x1, x2 );

	int cnt = 0;
	REP( y, mmy.fst, mmy.snd + 1 )
	{
		REP( x, mmx.fst, mmx.snd + 1 )
		{
			cnt += board[y][x] == 'x';
		}
	}
	return cnt <= 1;
}

void dfs( const int sy, const int sx, const int u )
{
	if ( SZ( G ) <= u )
	{
		G.resize( u + 1 );
		sizes.resize( u + 1 );
	}

	if ( board[ sy ][ sx ] == 'x' )
	{ // erase current loop
		queue< PII > que;
		que.EM( sy, sx );

		int cnt = 0;

		while ( !que.empty() )
		{
			const int y = que.front().fst;
			const int x = que.front().snd;
			que.pop();

			REP( dy, -1, 2 )
			{
				REP( dx, -1, 2 )
				{
					if ( !( dy | dx ) )
					{
						continue;
					}

					const int ny = y + dy;
					const int nx = x + dx;
					
					if ( !inside( ny, nx ) || board[ ny ][ nx ] == '.' )
					{
						continue;
					}

					++cnt;

					board[ ny ][ nx ] = '.';
					visited[ ny ][ nx ] = 2;
					que.EM( ny, nx );
				}
			}
		}

		sizes[u] = cnt;
	}

	VPII nexts;
	{ // find adjacenta loops
		queue< PII > que;
		que.EM( sy, sx );

		while ( !que.empty() )
		{
			const int y = que.front().fst;
			const int x = que.front().snd;
			que.pop();

			REP( dy, -1, 2 )
			{
				REP( dx, -1, 2 )
				{
					if ( !( dy | dx ) )
					{
						continue;
					}

					const int ny = y + dy;
					const int nx = x + dx;

					if ( !inside( ny, nx ) || visited[ ny ][ nx ] )
					{
						continue;
					}

					if ( board[ ny ][ nx ] == 'x' )
					{
						nexts.EB( ny, nx );
					}

					if ( throuable( y, x, ny, nx ) )
					{
						que.EM( ny, nx );
						visited[ ny ][ nx ] = true;
					}
				}
			}
		}
	}

	FOR( p, nexts )
	{
		const int y = p.fst;
		const int x = p.snd;

		if ( visited[y][x] == 2 )
		{
			continue;
		}

		visited[y][x] = true;

		G[u].PB( SZ( G ) );
		dfs( y, x, SZ( G ) );
	}

	return;
}


VVI dp;
int rec( const int u, const int f )
{
	int &res = dp[u][f];

	if ( res != -1 )
	{
		return res;
	}

	if ( f ) // use current node
	{
		int total = sizes[u];
		FOR( v, G[u] )
		{
			total += rec( v, 0 );
		}
		chmax( res, total );
	}
	{ // do not use current node
		int total = 0;
		FOR( v, G[u] )
		{
			total += max( rec( v, 0 ), rec( v, 1 ) );
		}
		chmax( res, total );
	}
	return res;
}

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );

	cin >> N >> M;

	board.resize( N );
	cin >> board;

	board.insert( begin( board ), string( M + 2, '.' ) );
	REP( i, 1, N + 1 )
	{
		board[i] = "." + board[i] + ".";
	}
	board.EB( M + 2, '.' );

	N += 2;
	M += 2;

	visited.resize( N, VI( M ) );

	dfs( 0, 0, 0 );

	const int V = SZ( sizes );

	dp.resize( V, VI( 2, -1 ) );
	cout << rec( 0, 0 ) << endl;

	return 0;
}