#include<bits/stdc++.h>
using namespace std;
int chess[5][5],n;
bool ispossible(int i,int j)
{
if(chess[i][j]==1 || chess[i][j]==-1) return false;
int ro,col,x,y;
for(ro=i+1;ro<n && chess[ro][j]!=-1;ro++)
{
if(chess[ro][j]==1)
return false;
}
for(ro=i-1; ro>=0 && chess[ro][j]!=-1; ro=ro-1)
{
if(chess[ro][j]==1) return false;
}
for(col=j+1; col<n && chess[i][col]!=-1; col++) {
if(chess[i][col]==1) return false;
}
for(col=j-1; col>=0 && chess[i][col]!=-1; col=col-1) {
if(chess[i][col]==1) return false;
}
return true;
}

int rook()
{
int cnt=0,i,j,res;

for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
if(ispossible(i,j)==true)
{ chess[i][j]=1;
res=1+rook();
cnt=max(cnt,res);
chess[i][j]=0;
}
}
}
return cnt;
}


int main()
{
while(cin>>n && n)
{
string s;
memset(chess,0,sizeof(chess));
int i,j;
for(i=0;i<n;i++)
{
cin>>s;
for(j=0;j<n;j++)
{
if(s[j]=='X')
chess[i][j]=-1;
}
}
int mn= rook();
cout<<mn<<endl;
}
return 0;
}