#include<iostream>
#include<cstdio>
using namespace std;
int h,w;
long long ans=0,b[50010]={},bq[50010]={}; 
void chu(int x,int y)
{
	int l=y-x+1;
	if(l<=0)
	{
		l=1;
	}
	int r=y+x-1;
	if(r>w)
	{
		r=w;
	}
	b[l]++;
	b[r+1]--;
}
int main()
{
	freopen("snow.in","r",stdin);
    freopen("snow.out","w",stdout);
	cin>>w>>h;
	for(int i=h;i>=1;i--)
	{
		for(int j=1;j<=w;j++)
		{
			char a;
			cin>>a;
			if(a=='*')
			{
				chu(i,j);
			}
		}
	}
	for(int i=1;i<=w;i++)
	{
		bq[i]=bq[i-1]+b[i];
		if(bq[i]>ans)
		{
			ans=bq[i];
		}
	}
	cout<<ans;
	return 0;
}