import java.awt.Polygon;
import java.awt.geom.Point2D;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.StringTokenizer;

/*
 * Created on 2004/09/20
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */

/**
 * @author horizon
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class D {

	
	
	public static boolean check(double x1,double y1,double x2,double y2,Polygon p)
	{
		if((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) < 0.001)
		{
			//return p.contains(x1,y1);
			double d = 0.001;
			return p.intersects(x1-d,y1-d,2*d,2*d);
		}
		else
		{
			double x = (x1 + x2) / 2.0;
			double y = (y1 + y2) / 2.0;
			return check(x1,y1,x,y,p) && check(x2,y2,x,y,p);			
		}		
		
	}
	
	public static void main(String[] args) throws Exception{
			
		BufferedReader r = new BufferedReader(new FileReader("video.txt"));  

		int count = 0;
		
		while(true){
						
			count++;
			
			int n = Integer.parseInt(r.readLine());
			
			if(n == 0)break;
			
			int[] x = new int[n];
			int[] y = new int[n];
			
			for(int i = 0;i < n;i++)
			{
				StringTokenizer st = new StringTokenizer(r.readLine());
				x[i] = Integer.parseInt(st.nextToken());
				y[i] = Integer.parseInt(st.nextToken());
			}
			
			
			Polygon pol = new Polygon(x,y,n);
			
			
			boolean ans = false;
			
			for(int h = 0;h < n;h++)
			{
				for(int i = 0;i < n;i++)
				{
					boolean flag = true;
					for(int j = 0;j < n;j++)
					{
						flag = flag && check(x[i],y[h],x[j],y[j],pol);
						if(!flag)break;
					}
					
					if(flag)
					{
						ans = true;
						break;
					}
				}
				if(ans)break;
			}
			System.out.print("Floor #");
			System.out.println(count);
			
			
			if(ans)
				System.out.println("Surveillance is possible.");
			else
				System.out.println("Surveillance is impossible.");

			System.out.println();
			
			
		
		}
	}
}