/*
Author: QAQAutomaton
Lang: C++
Code: C.cpp
Mail: lk@qaq-am.com
Blog: https://www.qaq-am.com/
*/
#include<bits/stdc++.h>
#define debug(...) fprintf(stderr,__VA_ARGS__)
#define DEBUG printf("Passing [%s] in LINE %d\n",__FUNCTION__,__LINE__)
#define Debug debug("Passing [%s] in LINE %d\n",__FUNCTION__,__LINE__)
#define all(x) x.begin(),x.end()
#define x first
#define y second
using namespace std;
typedef unsigned uint;
typedef long long ll;
typedef unsigned long long ull;
typedef complex<double> cp;
typedef pair<int,int> pii;
int inf;
const double eps=1e-8;
const double pi=acos(-1.0);
template<class T,class T2>int chkmin(T &a,T2 b){return a>b?a=b,1:0;}
template<class T,class T2>int chkmax(T &a,T2 b){return a<b?a=b,1:0;}
template<class T>T sqr(T a){return a*a;}
template<class T,class T2>T mmin(T a,T2 b){return a<b?a:b;}
template<class T,class T2>T mmax(T a,T2 b){return a>b?a:b;}
template<class T>T aabs(T a){return a<0?-a:a;}
template<class T>int dcmp(T a,T b){return a>b;}
template<int *a>int cmp_a(int x,int y){return a[x]<a[y];}
template<class T>bool sort2(T &a,T &b){return a>b?swap(a,b),1:0;}
#define min mmin
#define max mmax
#define abs aabs
struct __INIT__{
	__INIT__(){
		fill((unsigned char*)&inf,(unsigned char*)&inf+sizeof(inf),0x3f);
	}
}__INIT___;
namespace io {
	const int SIZE = (1 << 21) + 1;
	char ibuf[SIZE], *iS, *iT, obuf[SIZE], *oS = obuf, *oT = oS + SIZE - 1, c, qu[55]; int f, qr;
	// getchar
	#define gc() (iS == iT ? (iT = (iS = ibuf) + fread (ibuf, 1, SIZE, stdin), (iS == iT ? EOF : *iS ++)) : *iS ++)
	// print the remaining part
	inline void flush () {
		fwrite (obuf, 1, oS - obuf, stdout);
		oS = obuf;
	}
	// putchar
	inline void putc (char x) {
		*oS ++ = x;
		if (oS == oT) flush ();
	}
	template<typename A>
	inline bool read (A &x) {
		for (f = 1, c = gc(); c < '0' || c > '9'; c = gc()) if (c == '-') f = -1;else if(c==EOF)return 0;
		for (x = 0; c <= '9' && c >= '0'; c = gc()) x = x * 10 + (c & 15); x *= f;
		return 1;
	}
	inline bool read (char &x) {
		while((x=gc())==' '||x=='\n' || x=='\r');
		return x!=EOF;
	}
	inline bool read(char *x){
		while((*x=gc())=='\n' || *x==' '||*x=='\r');
		if(*x==EOF)return 0;
		while(!(*x=='\n'||*x==' '||*x=='\r'||*x==EOF))*(++x)=gc();
		*x=0;
		return 1;
	}
	template<typename A,typename ...B>
	inline bool read(A &x,B &...y){
		return read(x)&&read(y...);
	}
	template<typename A>
	inline bool write (A x) {
		if (!x) putc ('0'); if (x < 0) putc ('-'), x = -x;
		while (x) qu[++ qr] = x % 10 + '0',  x /= 10;
		while (qr) putc (qu[qr --]);
		return 0;
	}
	inline bool write (char x) {
		putc(x);
		return 0;
	}
	inline bool write(const char *x){
		while(*x){putc(*x);++x;}
		return 0;
	}
	inline bool write(char *x){
		while(*x){putc(*x);++x;}
		return 0;
	}
	template<typename A,typename ...B>
	inline bool write(A x,B ...y){
		return write(x)||write(y...);
	}
	//no need to call flush at the end manually!
	struct Flusher_ {~Flusher_(){flush();}}io_flusher_;
}
using io :: read;
using io :: putc;
using io :: write;
namespace mcmf{
	int n;
	int to[2000005],lst[2000005],beg[100005],w[2000005],c[2000005],e=1,ans,s,t;
	void add(int s,int t,int fl,int co){
		to[++e]=t;lst[e]=beg[s];beg[s]=e;w[e]=fl;c[e]=co;
		to[++e]=s;lst[e]=beg[t];beg[t]=e;w[e]=0;c[e]=-co;
	}
	int cur[100005],d[100005],inq[100005];
	int q[100005],*las=q+100004,*l,*r;
	int fl[100005],fr[100005];
	int spfa(){
		for(int i=1;i<=n;++i)d[i]=inf;
		d[s]=0;
		*(l=r=q)=s;
		fl[s]=inf;
		for(;;l==las?l=q:++l){
			inq[*l]=0;
			for(int i=beg[*l];i;i=lst[i])if(w[i]){
				if(chkmin(d[to[i]],d[*l]+c[i])){
					if(!inq[to[i]]){
						*(r==las?r=q:++r)=to[i];
 
						inq[to[i]]=1;
					}
					fr[to[i]]=i;
					fl[to[i]]=min(fl[*l],w[i]);
				}
			}
			if(l==r)break;
		}
		return d[t];
	}
	int calc(){
		int nex;
		while((nex=spfa())!=inf){
			ans+=nex*fl[t];
			for(int i=t;i!=s;i=to[fr[i]^1]){
				w[fr[i]]-=fl[t];
				w[fr[i]^1]+=fl[t];
			}
		}		
		return ans;
	}
}
char s[55][55];
int id[55][55];
signed main(){
#ifdef QAQAutoMaton 
	freopen("C.in","r",stdin);
	freopen("C.out","w",stdout);
#endif
	int n,m;	
	read(n,m);
	for(int i=1;i<=n;++i){
		read(s[i]+1);
	}
	int c=2;
	for(int i=1;i<=n;++i)for(int j=1;j<=m;++j)id[i][j]=++c;
	for(int i=1;i<=n;++i)for(int j=1;j<=m;++j){
		if(s[i][j]=='o')mcmf::add(1,id[i][j],1,0);
		mcmf::add(id[i][j],2,1,0);
		if(i<n && s[i][j]!='#' && s[i+1][j]!='#')mcmf::add(id[i][j],id[i+1][j],inf,-1);
		if(j<m && s[i][j]!='#' && s[i][j+1]!='#')mcmf::add(id[i][j],id[i][j+1],inf,-1);
	}
	mcmf::n=c;
	mcmf::s=1;
	mcmf::t=2;
	write(-mcmf::calc(),'\n');
	return 0;
}



Measured memory_bytes: 4024