#include <cstdio>

#include <vector>

#include <cstring>

using namespace std;

#define F(i,j,k) for (int i=j;i<=k;++i)

#define D(i,j,k) for (int i=j;i>=k;--i)

vector <int> v[3005];

int n,m,map[55][55],mx,ans;

int le[55][55],ri[55][55],vis[3005],linker[3005];

char s[55];

bool dfs(int o)

{

    for (int i=0;i<v[o].size();++i)

    if (!vis[v[o][i]]){

        vis[v[o][i]]=1;

        if (!linker[v[o][i]]||dfs(linker[v[o][i]]))

        {

            linker[v[o][i]]=o;

            return true;

        }

    }

    return false;

}

int main()

{

    scanf("%d%d",&n,&m);

    F(i,1,n)

    {

        scanf("%s",s+1);

        F(j,1,m)

            switch(s[j])

            {

                case '*': map[i][j]=1;break;

                case '#': map[i][j]=-1;break;

                case 'x': map[i][j]=0;break;

            }

    }

    F(i,0,n+1) map[i][0]=map[i][m+1]=-1;

    F(i,0,m+1) map[n+1][i]=map[0][i]=-1;

    int cnt=0,con=1;

    F(i,0,n) F(j,0,m)

        if (map[i][j]!=-1) con=1,le[i][j]=cnt;

        else{if (con) ++cnt,con=0;}

    mx=cnt;cnt=0,con=1;

    F(j,0,m) F(i,0,n)

        if (map[i][j]!=-1) con=1,ri[i][j]=cnt;

        else {if (con) ++cnt,con=0;}

    F(i,1,n) F(j,1,m)

        if (map[i][j]==1)

            v[le[i][j]].push_back(ri[i][j]);

    F(i,1,mx)

    {

        memset(vis,0,sizeof vis);

        if (dfs(i)) ans++;

    }

    printf("%d\n",ans);

}