import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;


/**
 * 
 */

/**
 * Sample solution for Collision Detection
 * 
 * @author zeil
 *
 */
public class CollisionDetection_zeil {
	
	private Scanner input;
	
	

	public CollisionDetection_zeil(Scanner in) {
		input = in;
	}


	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main (String[] argv) throws IOException
	{
		BufferedReader in;
		if (argv.length > 0)
		{
			in = new BufferedReader(new FileReader(argv[0]));
		}
		else {
			in = new BufferedReader (new InputStreamReader(System.in));
		}
		run (in);
	}
	
	
	final static void run (BufferedReader bin)
	{
		Scanner in = new Scanner(bin);
		boolean done = false;
		while (!done)
		{
			CollisionDetection_zeil problem = new CollisionDetection_zeil(in);
			done = problem.solve();
		}
	}

	class Observation {
		public double t, x, y, s;
		
		public Observation (Scanner in) {
			t = in.nextDouble();
			x = in.nextDouble();
			y = in.nextDouble();
			s = in.nextDouble();
		}
	}
	
	static final double SpeedLimit = 80.0; 
	
	class Car {
		// Info about the car during the first phase of its movement
		// when it is accelerating (or decelerating)
		public double a0;
		public double s0;
		public double x0;
		public double y0;
		public double t0;
		
		public double dx;
		public double dy;
		public double d1;
		
		public double t1; // time at which acceleration ends
		
		// Info about the car at time t1
		public double s1;
		public double x1;
		public double y1;
		
		
		public Car (Observation o1, Observation o2) {
			Observation older;
			Observation newer;
			
			if (o1.t < o2.t) {
				older = o1;
				newer = o2;
			} else {
				older = o2;
				newer = o1;
			}
			
			dx = newer.x - older.x;
			dy = newer.y - older.y;
			d1 = Math.sqrt(dx * dx + dy*dy);
			
			
			t0 = newer.t;
			s0 = newer.s;
			x0 = newer.x;
			y0 = newer.y;
			a0 = (newer.s - older.s) / (newer.t - older.t);
			
			if (a0 > 0.0) {
				// car is accelerating
				t1 = t0 + (SpeedLimit - s0) / a0;
				s1 = SpeedLimit;
			} else if (a0 < 0.0){
				// car is decelerating
				t1 = t0 - s0 / a0;
				s1 = 0.0;
			} else {
				t1 = t0+1;
				s1 = s0;
			}
			x1 = x(t1);
			y1 = y(t1);				
		}
		
		
		public double x(double t) {
			if (d1 == 0.0)
				return x0;
			if (t > t1) {
				double dt = t - t1;
				double d = s1 * dt;
				d = d * dx / d1;
				return x1 + d;
			} else {
				double dt = t - t0;
				double d = a0 * dt * dt / 2.0 + s0 * dt;
				d = d * dx / d1;
				return x0 + d;
			}
		}
		
		public double y(double t) {
			if (d1 == 0.0)
				return y0;
			if (t > t1) {
				double dt = t - t1;
				double d = s1 * dt;
				d = d * dy / d1;
				return y1 + d;
			} else {
				double dt = t - t0;
				double d = a0 * dt * dt / 2.0 + s0 * dt;
				d = d * dy / d1;
				return y0 + d;
			}
		}
		
	}
	
	public Car car1, car2;

	private boolean solve() {
		Observation o1 = new Observation(input);
		if (o1.t < 0.0)
			return true;
		Observation o2 = new Observation(input);
		car1 = new Car(o1, o2);
		
		Observation o3 = new Observation(input);
		Observation o4 = new Observation(input);
		car2 = new Car(o3, o4);
		
		double deltaT = 5.0 / 160.0; // time for two cars heading straight
		   // towards one another at top speed to reduce gap by 5.0 ft.  
		
		double t0 = Math.max(Math.max(o1.t, o2.t), Math.max(o3.t, o4.t));
		double dt = 0.0;
		boolean dangerous = false;
		double minD = Double.MAX_VALUE;
		double minT = 0.0;
		while (dt < 30.0 + deltaT /*&& !dangerous*/) {
			double t = t0 + Math.min(dt, 30.0);
			double x1 = car1.x(t);
			double y1 = car1.y(t);
			double x2 = car2.x(t);
			double y2 = car2.y(t);
			double dx = x1 - x2;
			double dy = y1 - y2;
			double d = Math.sqrt(dx*dx + dy * dy);
			if (d < minD) {
				minD = d;
				minT = t;
			}
			dangerous = dangerous || d < 18.0; // in contest I would use 19.0
			
			dt += deltaT;
		}
		if (dangerous) {
			System.out.println ("Dangerous");
		} else {
			System.out.println ("Safe");
		}
		//System.out.println ("(Min Distance occurred at t=" + minT + " and was " + minD + ")");
		
		return false;
	}


}