PLUS

#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#define ZERO (1e-10)
#define INF (1<<29)
#define CL(A,I) (memset(A,I,sizeof(A)))
#define DEB printf("DEB!\n");
#define D(X) cout<<"  "<<#X": "<<X<<endl;
#define EQ(A,B) (A+ZERO>B&&A-ZERO<B)
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;
#define IN(n) int n;scanf("%d",&n);
#define FOR(i, m, n) for (int i(m); i < n; i++)
#define REP(i, n) FOR(i, 0, n)
#define F(n) REP(i, n)
#define FF(n) REP(j, n)
#define FT(m, n) FOR(k, m, n)
#define aa first
#define bb second
void ga(int N,int *A){F(N)scanf("%d",A+i);}
#define MX (2048)
char s[MX][MX];
int N,U[MX][MX],L[MX][MX],R[MX][MX],B[MX][MX],X;
int main(void){
    IN(tt)F(tt){
        CL(B,0),CL(R,0);
        scanf("%d",&N),assert(N>0&&N<2001),X=0;
        F(N)scanf("%s",s[i]),assert(strlen(s[i])<2001);
        F(N)FF(N)assert(s[i][j]==35||s[i][j]==46);
        F(N)FF(N)U[i][j]=(s[i][j]==35)?1+(i?U[i-1][j]:0):0,
                 L[i][j]=(s[i][j]==35)?1+(j?L[i][j-1]:0):0;
        for(int i=N-1;~i;--i)for(int j=N-1;~j;--j)
                B[i][j]=(s[i][j]==35)?1+B[i+1][j]:0,
                R[i][j]=(s[i][j]==35)?1+R[i][j+1]:0;
        F(N)FF(N)X=max(X,min(U[i][j],min(L[i][j],min(R[i][j],B[i][j]))));
        printf("%d\n",X);
    }
    return 0;
}