#include <iostream>

 #include <stdio.h>

 #include <memory.h>

 using namespace std;

 char a[][]= {};

 int down[][]= {};

 int up[][]= {};

 int cnt[][][]= {};

 int n;

 int dx[]= {-,,-, };

 int dy[]= {-,, ,-};

 int dfs(int curx,int cury,int num)

 {

     if(curx< || cury< || curx>=n || cury>=n)

         return ;

     int &ans=cnt[curx][cury][num];

     if(a[curx][cury]=='#')

         return ans=;

     return ans=+dfs(curx+dx[num],cury+dy[num],num);

 }

 int getMax()

 {

     int ans=;

     for(int i=; i<n; i++)

         for(int j=; j<n; j++)

         {

             ans=max(ans,down[i][j]+up[i][j]-);

         }

     return ans;

 }

 int main()

 {

     freopen("in.txt","r",stdin);

     while(scanf("%d",&n),n)

     {

         memset(down,,sizeof down);

         memset(up,,sizeof up);

         memset(cnt,,sizeof cnt);

         for(int i=; i<n; i++)

             scanf("%s",a[i]);

         for(int i=; i<n; i++)

             for(int j=; j<n; j++)

             {

                 if(a[i][j]=='#')

                 {

                     up[i][j]=down[i][j]=;

                 }

                 else

                 {

                     up[i][j]=down[i][j]=;

                     if(i!=)

                         up[i][j]=up[i-][j]+;

                     if(j!=)

                         down[i][j]=down[i][j-]+;

                 }

             }

         int ans=;

         ans=max(ans,getMax());

         memset(down,,sizeof down);

         memset(up,,sizeof up);

         for(int i=n-; i>=; i--)

             for(int j=n-; j>=; j--)

             {

                 if(a[i][j]=='#')

                 {

                     up[i][j]=down[i][j]=;

                 }

                 else

                 {

                     up[i][j]=down[i][j]=;

                     if(i!=n-)

                         up[i][j]=up[i+][j]+;

                     if(j!=n-)

                         down[i][j]=down[i][j+]+;

                 }

             }

         ans=max(ans,getMax());

 //---------------------------

         memset(down,,sizeof down);

         memset(up,,sizeof up);

         for(int i=; i<n; i++)

             for(int j=n-; j>=; j--)

             {

                 if(a[i][j]=='#')

                 {

                     up[i][j]=down[i][j]=;

                 }

                 else

                 {

                     up[i][j]=down[i][j]=;

                     if(i!=)

                         up[i][j]=up[i-][j]+;

                     if(j!=n-)

                         down[i][j]=down[i][j+]+;

                 }

             }

         ans=max(ans,getMax());

 //-------------------------------

         memset(down,,sizeof down);

         memset(up,,sizeof up);

         for(int i=n-; i>=; i--)

             for(int j=; j<n; j++)

             {

                 if(a[i][j]=='#')

                 {

                     up[i][j]=down[i][j]=;

                 }

                 else

                 {

                     up[i][j]=down[i][j]=;

                     if(i!=n-)

                         up[i][j]=up[i+][j]+;

                     if(j!=)

                         down[i][j]=down[i][j-]+;

                 }

             }

         ans=max(ans,getMax());

 //--------------------------------------------------

         for(int i=; i<n; i++)

             for(int j=; j<n; j++)

             {

                 for(int num=; num<; num++)

                 {

                     dfs(i,j,num);

                 }

             }

         for(int i=; i<n; i++)

             for(int j=; j<n; j++)

             {

                 ans=max(ans,cnt[i][j][]+cnt[i][j][]-);

                 ans=max(ans,cnt[i][j][]+cnt[i][j][]-);

                 ans=max(ans,cnt[i][j][]+cnt[i][j][]-);

                 ans=max(ans,cnt[i][j][]+cnt[i][j][]-);

             }

         cout<<ans<<endl;

     }

     return ;

 }