#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define R cin>>
#define Z class
#define ll long long
#define ln cout<<'\n'
#define in(a) insert(a)
#define pb(a) push_back(a)
#define pd(a) printf("%.10f\n",a)
#define mem(a) memset(a,0,sizeof(a))
#define all(c) (c).begin(),(c).end()
#define iter(c) __typeof((c).begin())
#define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define REP(i,m,n) for(ll i=(ll)(m);i<(ll)(n);i++)
#define rep(i,n) REP(i,0,n)
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
template<Z A>void pr(A a){cout<<a;ln;}
template<Z A,Z B>void pr(A a,B b){cout<<a<<' ';pr(b);}
template<Z A,Z B,Z C>void pr(A a,B b,C c){cout<<a<<' ';pr(b,c);}
template<Z A,Z B,Z C,Z D>void pr(A a,B b,C c,D d){cout<<a<<' ';pr(b,c,d);}
template<Z A>void PR(A a,ll n){rep(i,n){if(i)cout<<' ';cout<<a[i];}ln;}
ll check(ll n,ll m,ll x,ll y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1e9+7,MAXL=1LL<<61,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

vector<string> rotate(vector<string> s) {
  int n=s.size(),m=s[0].size();
  vector<string> t(m);
  rep(i,m)rrep(j,n) t[i]+=s[j][i];
  return t;
}

void Main() {
  int n;
  cin >> n;
  vector<string> s(n);
  rep(i,n) cin >> s[i];
  int ans=0;
  rep(l,4) {
    rep(r,2) {
      int c=0,sum=0;
      rep(j,n-1) if(s[0][j]=='.') c++;
      int d[n][2];mem(d);
      rep(j,n) {
        rep(i,n-1) if(s[i][j]=='.') d[j][0]++;
        REP(i,1,n) if(s[i][j]=='.') d[j][1]++;
        rep(i,2) d[j][i]=d[j][i]==n-1;
      }
      if(c==n-1) {
        sum++;
        rep(j,n-1) sum+=d[j][1];
        sum+=d[n-1][0]||d[n-1][1];
        ans=max(ans,sum);
      }
      sum=0;
      rep(j,n) sum+=d[j][0]||d[j][1];
      ans=max(ans,sum);
      rep(i,n) reverse(all(s[i]));
    }
    s=rotate(s);
  }
  int c[4];mem(c);
  rep(i,n) {
    c[0]+=s[i][0]=='.';
    c[1]+=s[0][i]=='.';
    c[2]+=s[i][n-1]=='.';
    c[3]+=s[n-1][i]=='.';
  }
  bool f=1;
  rep(i,4) f&=c[i]==n;
  if(f) ans=max(ans,4);
  pr(ans);
}

int main(){ios::sync_with_stdio(0);cin.tie(0);Main();return 0;}