Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	x := make([]int, 100)
	y := make([]int, 100)
	r := make([]int, 100)
	for scanner.Scan() {
		a, _ := strconv.Atoi(scanner.Text())
		if a == 0 {
			break
		}
		for i := 0; i < a; i++ {
			scanner.Scan()
			input := strings.Split(scanner.Text(), " ")
			tmpx, _ := strconv.Atoi(input[0])
			tmpy, _ := strconv.Atoi(input[1])
			tmpr, _ := strconv.Atoi(input[2])
			x[i], y[i], r[i] = tmpx, tmpy, tmpr
		}
		scanner.Scan()
		b, _ := strconv.Atoi(scanner.Text())
		for i := 0; i < b; i++ {
			scanner.Scan()
			input := strings.Split(scanner.Text(), " ")
			c, _ := strconv.Atoi(input[0])
			d, _ := strconv.Atoi(input[1])
			e, _ := strconv.Atoi(input[2])
			f, _ := strconv.Atoi(input[3])
			ok := false
			for j := 0; j < a; j++ {
				if (c-x[j])*(c-x[j])+(d-y[j])*(d-y[j]) >= r[j]*r[j] || (e-x[j])*(e-x[j])+(f-y[j])*(f-y[j]) >= r[j]*r[j] {
					if (e-c)*(x[j]-c)+(f-d)*(y[j]-d) < 0 {
						if (x[j]-c)*(x[j]-c)+(y[j]-d)*(y[j]-d) <= r[j]*r[j] {
							ok = true
						}
					} else {
						if (e-c)*(x[j]-c)+(f-d)*(y[j]-d)>(e-c)*(e-c)+(f-d)*(f-d) {
							if (x[j]-e)*(x[j]-e)+(y[j]-f)*(y[j]-f)<=r[j]*r[j] {
								ok = true
							}
						} else {
							if (x[j]-c)*(x[j]-c)+(y[j]-d)*(y[j]-d)-((e-c)*(x[j]-c)+(f-d)*(y[j]-d))*((e-c)*(x[j]-c)+(f-d)*(y[j]-d))/((e-c)*(e-c)+(f-d)*(f-d))<=r[j]*r[j] {
								ok = true
							}
						}
					}

				}
			}
			if ok {
				fmt.Println("Safe")
			} else {
				fmt.Println("Danger")
			}
		}
	}
}

C++: #include<iostream>
#include<cfloat>
#include<cassert>
#include<cmath>
#include<vector>
#include<algorithm>
#include<stdio.h>
using namespace std;

#define EPS (1e-10)
#define equals(a, b) (fabs((a) - (b)) < EPS )
#define dle(a, b) (equals(a, b) || a < b )
static const double PI = acos(-1);

class Point{
public:
  double x, y;
  
  Point ( double x = 0, double y = 0): x(x), y(y){}
  
  Point operator + ( Point p ){ return Point(x + p.x, y + p.y); }
  Point operator - ( Point p ){ return Point(x - p.x, y - p.y); }
  Point operator * ( double a ){ return Point(x*a, y*a); }
  Point operator / ( double a ){ return Point(x/a, y/a); }
  
  double abs() { return sqrt(norm());}
  double norm() { return x*x + y*y; }
  
  bool operator < ( const Point &p ) const {
    return x != p.x ? x < p.x : y < p.y;
  }
  
  bool operator == ( const Point &p ) const {
    return fabs(x-p.x) < EPS && fabs(y-p.y) < EPS;
  }
};

class Segment{
public:
  Point p1, p2;
  Segment ( Point p1 = Point(0.0,0.0), Point p2 = Point(0.0,0.0)): p1(p1), p2(p2){}
  double abs() { return sqrt(norm());}
  double norm() { return (p2.x - p1.x)*(p2.x - p1.x) + (p2.y - p1.y)*(p2.y - p1.y); }
};
typedef Segment Line;
typedef Point Vector;
typedef vector<Point> Polygon;
double norm( Vector a ){ return a.x*a.x + a.y*a.y; }
double abs( Vector a ){ return sqrt(norm(a)); }
Point polar( double a, double r ){ return Point(cos(r)*a, sin(r)*a);}
double getDistance( Vector a, Vector b ){ return abs(a - b); }
double dot( Vector a, Vector b ){ return a.x*b.x + a.y*b.y; }
double cross( Vector a, Vector b ){ return a.x*b.y - a.y*b.x; }
bool isOrthogonal( Vector a, Vector b){
  return equals(dot(a,b),0.0);
}
bool isOrthogonal(Segment s1,Segment s2){
  return equals( dot(s1.p2-s1.p1 , s2.p2-s2.p1) ,0.0 );
}
bool isParallel(Vector a, Vector b){
  return equals(cross(a,b),0.0);
}
bool isParallel(Point a1,Point a2,Point b1,Point b2){
  return isParallel(a1-a2,b1-b2);
}
bool isParallel(Segment s1,Segment s2){
  return equals(cross(s1.p2 - s1.p1 , s2.p2 - s2.p1),0.0);
}
Point project(Segment s,Point p){
  Vector base = s.p2-s.p1;
  double t = dot(p-s.p1,base)/norm(base);
  return s.p1+base*t;
}
Point reflect(Segment s,Point p){
  return p + (project(s,p)-p)*2.0;
}

static const int COUNTER_CLOCKWISE = 1;
static const int CLOCKWISE = -1;
static const int ONLINE_BACK = 2;
static const int ONLINE_FRONT = -2;
static const int ON_SEGMENT = 0;
 
// EPS can be 0
// need to check for 920, 833, 866
int ccw( Point p0, Point p1, Point p2 ){
    Vector a = p1 - p0;
    Vector b = p2 - p0;
    if ( cross(a, b) > EPS ) return COUNTER_CLOCKWISE;
    if ( cross(a, b) < -EPS ) return CLOCKWISE;
    if ( dot(a, b) < -EPS ) return ONLINE_BACK;
    if ( norm(a) < norm(b) ) return ONLINE_FRONT;
    return ON_SEGMENT;
}

bool isIntersect(Point p1, Point p2,Point p3,Point p4){
  return (ccw(p1,p2,p3) * ccw(p1,p2,p4) <=0 &&
	  ccw(p3,p4,p1) * ccw(p3,p4,p2) <=0);
}

bool isIntersect(Segment s1,Segment s2){
  return isIntersect(s1.p1 , s1.p2 , s2.p1 , s2.p2);
}

Point getCrossPoint(Segment s1,Segment s2){
  assert(isIntersect(s1,s2));
  Vector base = s2.p2 - s2.p1;
  double d1 = abs(cross(base, s1.p1-s2.p1));
  double d2 = abs(cross(base, s1.p1-s2.p1));
  double t = d1/(d1+d2);
  return s1.p1 + (s1.p2 - s1.p1)*t;
}

double getDistanceLP(Line s,Point p){
  return abs(cross(s.p2-s.p1,p-s.p1)/abs(s.p2-s.p1));
}

double getDistanceSP(Segment s,Point p){
  if(dot(s.p2-s.p1,p-s.p1)<0.0)return abs(p-s.p1);
  if(dot(s.p1-s.p2,p-s.p2)<0.0)return abs(p-s.p2);
  return getDistanceLP(s,p);
}

double getDistance(Segment s1,Segment s2){
  if(isIntersect(s1,s2))return 0.0;
  return min(min(getDistanceSP(s1,s2.p1),getDistanceSP(s1,s2.p2)),
	     min(getDistanceSP(s2,s1.p1),getDistanceSP(s2,s1.p2)));
}

bool isConvex( Point P[4] ){
    int c = ccw(P[0], P[1], P[2]);
    for ( int i = 1; i < 4; i++ ){
      if ( c != ccw(P[i], P[(i+1)%4], P[(i+2)%4] )) return false;
    }
    return true;
}
bool isConvex( vector<Point> P ){
    int c = ccw(P[0], P[1], P[2]);
    for ( int i = 1; i < 4; i++ ){
      if ( c != ccw(P[i], P[(i+1)%4], P[(i+2)%4] )) return false;
    }
    return true;
}

Polygon andrewScan(Polygon s){
  Polygon u,l;
  if(s.size()<3)return s;
  sort(s.begin(),s.end());
  u.push_back(s[0]);
  u.push_back(s[1]);
  l.push_back(s[s.size()-1]);
  l.push_back(s[s.size()-2]);
  
  //int n;
  for(int i=2;i<(int)s.size();i++){
    for(int n=u.size();n>=2&&ccw(u[n-2],u[n-1],s[i])!=CLOCKWISE;n--){
      u.pop_back();
    }
    u.push_back(s[i]);
  }
  
  for(int i=s.size()-3;i>=0;i--){
    for(int n=l.size();n>=2&&ccw(l[n-2],l[n-1],s[i])!=CLOCKWISE;n--){
      l.pop_back();
    }
    l.push_back(s[i]);
  }
  
  reverse(l.begin(),l.end());
  for(int i=u.size()-2;i>=1;i--)l.push_back(u[i]);
  
  return l;
}

Point t[100];
double r[100];
Segment s;
bool check();
int n,m;
int main(){
  while(cin>>n){
    if(n==0)break;
    for(int i=0;i<n;i++){
      cin>>t[i].x>>t[i].y>>r[i];
    }
    cin>>m;

    for(int i=0;i<m;i++){
      cin>>s.p1.x>>s.p1.y>>s.p2.x>>s.p2.y;
      if(check()){
	cout<<"Safe"<<endl;
      }else{
	cout<<"Danger"<<endl;
      }
    }

  }
  return 0;
}
bool check(){
  double a,b,c;
  for(int i=0;i<n;i++){
    a=getDistance(s.p1,t[i]);
    b=getDistance(s.p2,t[i]);
    c=getDistanceSP(s,t[i]);
    if(a<r[i]&&b>r[i])return true;
    if(b<r[i]&&a>r[i])return true;
    if(a>=r[i]&&b>=r[i]&&c<=r[i])return true;
    
  }
  return false;
}