#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define REPR(i,n) for (int i=(int)(n)-1;i>=0;--i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define valid(y,x,h,w) (0<=y&&y<h&&0<=x&&x<w)
#define tpl(...) make_tuple(__VA_ARGS__)
const int INF = 0x3f3f3f3f;
const double EPS = 1e-8;
const double PI = acos(-1);
const int dy[] = {-1,0,1,0};
const int dx[] = {0,1,0,-1};
typedef long long ll;
typedef pair<int,int> pii;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<typename Ch,typename Tr,typename C,typename=decltype(begin(C()))>basic_ostream<Ch,Tr>& operator<<(basic_ostream<Ch,Tr>&os,
const C& c){os<<'[';for(auto i=begin(c);i!=end(c);++i)os<<(i==begin(c)?"":" ")<<*i;return os<<']';}
template<class S,class T>ostream&operator<<(ostream &o,const pair<S,T>&t){return o<<'('<<t.first<<','<<t.second<<')';}
template<int N,class Tp>void output(ostream&,const Tp&){}
template<int N,class Tp,class,class ...Ts>void output(ostream &o,const Tp&t){if(N)o<<',';o<<get<N>(t);output<N+1,Tp,Ts...>(o,t);}
template<class ...Ts>ostream&operator<<(ostream&o,const tuple<Ts...>&t){o<<'(';output<0,tuple<Ts...>,Ts...>(o,t);return o<<')';}
template<class T>void output(T t,char z=10){if(t<0)t=-t,putchar(45);int c[20];
int k=0;while(t)c[k++]=t%10,t/=10;for(k||(c[k++]=0);k;)putchar(c[--k]^48);putchar(z);}
template<class T>void outputs(T t){output(t);}
template<class S,class ...T>void outputs(S a,T...t){output(a,32);outputs(t...);}
template<class T>void output(T *a,int n){REP(i,n)cout<<a[i]<<(i!=n-1?',':'\n');}
template<class T>void output(T *a,int n,int m){REP(i,n)output(a[i],m);}
template<class T>bool input(T &t){int n=1,c;for(t=0;!isdigit(c=getchar())&&~c&&c-45;);
if(!~c)return 0;for(c-45&&(n=0,t=c^48);isdigit(c=getchar());)t=10*t+c-48;t=n?-t:t;return 1;}
template<class S,class ...T>bool input(S&a,T&...t){input(a);return input(t...);}
template<class T>bool inputs(T *a, int n) { REP(i,n) if(!input(a[i])) return 0; return 1;}

template<int H, int W>
struct GridLeg {
  int h,w;
  bool a[H][W];
  int b[H][W][4]; // up,right,down,left
  void init(int _h, int _w) {
    h=_h,w=_w;
    REP(i,h)REP(j,w) {
      a[i][j]=0;
      REP(k,4) b[i][j][k]=0;
    }
  }
  void run() {
    REP(i,h) {
      REP(j,w) {
        if (a[i][j]) {
          b[i][j][0]=(i?b[i-1][j][0]:0)+1;
          b[i][j][3]=(j?b[i][j-1][3]:0)+1;
        } else REP(k,4) b[i][j][k]=0;
      }
    }
    REPR(i,h) {
      REPR(j,w) {
        if (a[i][j]) {
          b[i][j][2]=(i+1<h?b[i+1][j][2]:0)+1;
          b[i][j][1]=(j+1<w?b[i][j+1][1]:0)+1;
        }
      }
    }
  }
  inline int operator()(int i, int j, int k) {return b[i][j][k];}
};

typedef GridLeg<2001,2001> Grid;

int l[2001];
int r[2001];
int u[2001];
int d[2001];
string s[2001];

Grid grid;

int main() {
  int h, w;
  while(input(h,w)) {
    grid.init(h,w);
    REP(i,h) {
      cin >> s[i];
    }
    REP(i,h) {
      REP(j,w) {
        grid.a[i][j] = (s[i][j] == '.');
      }
    }
    grid.run();
    int ans = 0;
    REP(i,h) {
      REP(j,w) {
        // printf("%d%c", grid(i,j,0), j!=w-1?' ':'\n');
        if (grid.a[i][j]) {
          chmax(ans, grid(i,j,0)+grid(i,j,1)+grid(i,j,2)+grid(i,j,3)-3);
        }
      }
    }
    cout << ans << endl;
  }
}


Measured memory_bytes: 70784