import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static int count = 0;

	public static int maxwidth = 0;
	
	public static int minwidth = 0;
	
	public static int maxheight = 0;
	
	public static int minheight = 0;
	
	public static boolean maxheight(ArrayList a) {
		int x = 0;
		int y = 0;
		int height = 0;
		int maxx1 = 0;
		int maxx2 = 0;
		int minX1 = 0;
		int minX2 = 0;
		int maxheight = 0;
		int I = 0;
		int K = 0;
		boolean getaccess = false ;
		for (int i = 0; i < a.size() / 2; i++) {
			String str = a.get(i).toString();
			String[] strgroup = str.split(" ");
			x = Integer.parseInt(strgroup[0]);
			y = Integer.parseInt(strgroup[1]);
			
			for(int k=i + a.size()/2; k<a.size(); k++ ) {
				String str2 = a.get(k).toString();
				String[] strgroup2 = str.split(" ");
				int X = Integer.parseInt(strgroup[0]);
				int Y = Integer.parseInt(strgroup[1]);
				height = Math.abs(Y - y);
				if(height > maxheight) {
					maxheight = height;
					I = i;
					K = k;
				}
			}
		}
		maxx1 = Integer.parseInt(a.get(I).toString().split(" ")[0]);
		maxx2 = Integer.parseInt(a.get(I + 1).toString().split(" ")[0]);
		minX1 = Integer.parseInt(a.get(K + 1).toString().split(" ")[0]);
		minX2 = Integer.parseInt(a.get(K).toString().split(" ")[0]);
		if(maxx1 > minX2 || maxx2 < minX1) {
			getaccess = false;
		}else {
			getaccess = true;
		}
		return getaccess;
	}
	

	public static boolean maxwidth(ArrayList a) {
		int x = 0;
		int y = 0;
		int width = 0;
		int maxy1 = 0;
		int maxy2 = 0;
		int minY1 = 0;
		int minY2 = 0;
		int maxwidth = 0;
		int I = 0;
		int K = 0;
		boolean getaccess = false ;
		for (int i = 0; i < a.size() / 2; i++) {
			String str = a.get(i).toString();
			String[] strgroup = str.split(" ");
			x = Integer.parseInt(strgroup[0]);
			y = Integer.parseInt(strgroup[1]);
			
			for(int k=i + a.size()/2; k<a.size(); k++ ) {
				String str2 = a.get(k).toString();
				String[] strgroup2 = str.split(" ");
				int X = Integer.parseInt(strgroup[0]);
				int Y = Integer.parseInt(strgroup[1]);
				width = Math.abs(X - x);
				if(width > maxwidth) {
					maxwidth = width;
					I = i;
					K = k;
				}
			}
		}
		maxy1 = Integer.parseInt(a.get(I).toString().split(" ")[1]);
		maxy2 = Integer.parseInt(a.get(I + 1).toString().split(" ")[1]);
		minY1 = Integer.parseInt(a.get(K + 1).toString().split(" ")[1]);
		minY2 = Integer.parseInt(a.get(K).toString().split(" ")[1]);
		if(maxy1 > minY2 || maxy2 < minY1) {
			getaccess = false;
		}else {
			getaccess = true;
		}
		return getaccess;
	}
	
	public static int getheight(ArrayList a) {
		int height = 0;
		ArrayList str1 = new ArrayList();
		ArrayList str2 = new ArrayList();
		
		for (int i = 0; i < a.size(); i++) {
			String str = a.get(i).toString();
			String[] strgroup = str.split(" ");
			str2.add(strgroup[1]);
			String s = str2.get(i).toString();
			int c = Integer.parseInt(s);
			if (c - maxheight > 0) {
				maxheight = c;
			}
		}
		for (int i = 0; i < a.size(); i++) {
			String s = str2.get(i).toString();
			int c = Integer.parseInt(s);
			if (c - minheight < 0) {
				minheight = c;
			}
		}
		height = maxheight - minheight;
		return height;
	}

	public static int getwidth(ArrayList b) {
		int width = 0;
		ArrayList str1 = new ArrayList();
		ArrayList str2 = new ArrayList();
		
		for (int i = 0; i < b.size(); i++) {
			String str = b.get(i).toString();
			String[] strgroup = str.split(" ");
			str2.add(strgroup[0]);
			String s = str2.get(i).toString();
			int c = Integer.parseInt(s);
			if (c - maxwidth > 0) {
				maxwidth = c;
			}
		}
		for (int i = 0; i < b.size(); i++) {
			String s = str2.get(i).toString();
			int c = Integer.parseInt(s);
			if (c - minwidth < 0) {
				minwidth = c;
			}
		}
		width = maxwidth - minwidth;
		return width;
	}

	public static void mysubtraction(Object object, Object object2,
			ArrayList<Integer> a, ArrayList<Integer> b) {
		String str1 = object.toString();
		String str2 = object2.toString();

		if (str1.charAt(0) - str2.charAt(0) == 0) {
			b.add(Math.abs(str1.charAt(2) - str2.charAt(2)));
		} else if (str1.charAt(2) - str2.charAt(2) == 0) {
			a.add(Math.abs(str1.charAt(0) - str2.charAt(0)));
		}
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.nextLine();
		while (Integer.parseInt(str) != 0) {
			String strr = sc.nextLine();
			ArrayList num = new ArrayList();
			if (str.split(" ").length == 1) {
				count++;
			}
			while (strr.length() != 1) {
				num.add(strr);
				strr = sc.nextLine();
			}
			ArrayList<Integer> leftright = new ArrayList<Integer>();
			ArrayList<Integer> updown = new ArrayList<Integer>();
			for (int k = 0; k < num.size(); k++) {
				if (k < num.size() - 1) {
					mysubtraction(num.get(k + 1), num.get(k), leftright, updown);
				} else {
					mysubtraction(num.get(num.size() - 1), num.get(0),
							leftright, updown);
				}
			}
			int leftrightsum = 0;
			int updownsum = 0;
			for (int k = 0; k < leftright.size(); k++) {
				leftrightsum = leftrightsum + leftright.get(k);
			}
			for (int k = 0; k < updown.size(); k++) {
				updownsum = updownsum + updown.get(k);
			}
			int width = getwidth(num);
			int height = getheight(num);
			if (leftrightsum == 2 * width && updownsum == 2 * height) {
				if (maxwidth(num)  == true  &&  maxheight(num) == true) {
					System.out.println("Floor #" + count);
					System.out.println("Surveillance is possible.");
				} else {
					System.out.println("Floor #" + count);
					System.out.println("Surveillance is impossible.");
				}
			} else {
				System.out.println("Floor #" + count);
				System.out.println("Surveillance is impossible.");
			}
			str = strr;

		}
	}
}