#include<bits/stdc++.h>
using namespace std;
int f[500010],d[500010];
int ans,w,h;
void work(int i,int j)
{
    if(i==h) f[j]++;
            else
            {
                if(j-h+i<=0&&j+h-i>w)
                {
                   d[1]++;d[w+1]--;
                }
                if(j+i-h<=0&&j+h-i<=w)
                {
                   d[1]++;d[j+h-i+1]--;
                 }
                 if(j+i-h>0&&j+h-i>w)
                 {
                    d[j+i-h+1]++;d[w+1]--;
                 }
                 if(j+i-h>0&&j+h-i<=w)
                 {
                     d[j+i-h+1]++;d[j+h-i+1]--;
                }
            }
}
int main()
{
    freopen("snow.in","r",stdin);
    freopen("snow.out","w",stdout);
    cin>>w>>h;
    memset(f,0,sizeof(f));
    for(int i=1;i<=h;i++)
    for(int j=1;j<=w;j++)
    {
        char a;
        cin>>a;
        if(a=='*') 
        {
            work(i,j);
        }
    }
    for(int i=1;i<=w;i++)
    {
        f[i]=f[i-1]+d[i];
        ans=max(ans,f[i]);
    }
    cout<<ans<<endl;
    return 0;
}