C++ :

#include<bits/stdc++.h>
using namespace std;
int n,m,a[55][55],ans;
char c;
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
		{
			cin>>c;
			if(c=='.') a[i][j]=0;
			else a[i][j]=1;
		}
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			a[i][0]+=a[i][j];
	for(int j=1;j<=m;j++)
		for(int i=1;i<=n;i++)
			a[n+1][j]+=a[i][j];
	for(int i=1;i<=n;i++)
	{
		if(a[i][0]==0)
			for(int j=1;j<=m;j++)
				if(a[n+1][j]==0) ans++;
	}
	cout<<ans;
    return 0;
}
/*
6 9
..#......
.........
.###..#..
.#.##..#.
...#..#..
.........
*/