#include<bits/stdc++.h>
using namespace std;
/*#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
/*template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
*/typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;

#define LOCAL 0
#define dbg(x) cout << #x << " is " << x << "\n"
#define gll(x) scanf("%d",&x)
#define gll2(x,y) scanf("%d%d",&x,&y)
#define gll3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define gllarr(arr,n) f(i,n) gll(arr[i]);
#define sz(x) ((int)x.size())
#define s(x) sort(x.begin(),x.end())
#define all(v) v.begin(),v.end()
#define rs(v) { s(v) ; r(v) ; }
#define r(v) {reverse(all(v));}
#define pb push_back
#define f(i,n) for(int i=0;i<n;i++)
#define fr(i,n) for(int i=n-1;i>=0;i--)
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define repr(i,a,b) for(int i=a;i>=b;i--)

const ll mod = (ll)1e9 + 7;
const ll inf = (ll)1e16;
const ld eps = 1e-12;
const ll N = (int)1e5 + 5;
const ll LOGN = 19;
const ld PI = 3.14159265358979323846;
inline ll mul(ll a, ll b, ll m = mod) { return (ll)(a * b) % m;}
inline ll add(ll a, ll b, ll m = mod) { a += b; if(a >= m) a -= m; if(a < 0) a += m; return a;}
inline ll power(ll a, ll b, ll m = mod) { if(b == 0) return 1; if(b == 1) return (a % m); ll x = power(a, b / 2, m); x = mul(x, x, m); if(b % 2) x = mul(x, a, m); return x;}

int n, m;
int dp[2005][2005][4];
int a[2005][2005];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    if (LOCAL) {
        freopen("C:\\Users\\Dishant\\Desktop\\Collection-DEV c++\\input.txt", "r", stdin);
        freopen("C:\\Users\\Dishant\\Desktop\\Collection-DEV c++\\output.txt", "w", stdout);
    }
    cin>>n>>m;
    f(i, n + 2){
        f(j, m + 2) a[i][j] = 1;
    }
    f(i, n) {
        string s;
        cin>>s;
        f(j, m){
            if(s[j] == '.') a[i + 1][j + 1] = 0;
            else a[i + 1][j + 1] = 1;
        }
    }
    n += 2, m += 2;
    int ans = 0;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < m; j++){
            if(a[i][j] == 1) {
                int cnt = 1;
                for(int k = i + 1; k < n; k++){
                    if(a[k][j] == 1) break;
                    dp[k][j][0] = i;
                    cnt++;
                }
                cnt = 1;
                for(int k = i - 1; k >= 0; k--){
                    if(a[k][j] == 1) break;
                    dp[k][j][1] = i;
                    cnt++;
                }
                cnt = 1;
                for(int k = j + 1; k < m; k++){
                    if(a[i][k] == 1) break;
                    dp[i][k][2] = j;
                    cnt++;
                }
                cnt = 1;
                for(int k = j - 1; k >= 0; k--){
                    if(a[i][k] == 1) break;
                    dp[i][k][3] = j;
                    cnt++;
                }
            }
        }
    }
    f(i, n) {
        f(j, m){
            //cout<<dp[i][j][0]<<' ';
            if(a[i][j] == 1) continue;
            int cans = dp[i][j][1] - i + i - dp[i][j][0] + j - dp[i][j][2] + dp[i][j][3] - j - 3;
            ans = max(ans, cans);
        }
        //cout<<endl;
    }
    cout<<ans;
    return 0;
}

Measured memory_bytes: 78720