#include<iostream>
#define NMAX 101
using namespace std;
short N,M;
char a[NMAX][NMAX];
int nrmaxp=0,nrp=1;
const int dx[2]={0,1};
const int dy[2]={1,0};
void citire(){
    cin>>N;
    cin>>M;
    short i,j;
    for(i=1;i<=N;i++){
        for(j=1;j<=M;j++)
            cin>>a[i][j];
    }
}
bool inside(int i,int j){
    return i>=1 && j>=1 && i<=4 && j<=4;
}
void alege(){
    if(nrp>nrmaxp)
        nrmaxp=nrp;
}
void BK(int i,int j){
     int inou,jnou;
     short p,ok=0;
     for(p=0;p<=1;p++){
        inou=i+dx[p];
        jnou=j+dy[p];
        if(inside(inou,jnou) && a[inou][jnou]=='.'){
            nrp++;
            BK(inou,jnou);
            nrp--;
        }
        else{
            ok++;
            if(ok==2)
                alege();
        }
     }
}
int main(){
    citire();
    BK(1,1);
    cout<<nrmaxp;
    return 0;
}