//horizon
#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <functional>
#include <cmath>
#include <cstring>

using namespace std;

struct Point
{
  int x, y;
};

int n;
Point input[100];

int TriS(Point& a,  Point& b, Point& c)
{
  return abs((b.y - a.y)*(c.x - a.x) - (c.y - a.y)*(b.x - a.x));
}

int PoriS(Point& p)
{
  int r = 0;
  for(int i = 0; i < n-1; ++i) {
    r += TriS(p, input[i], input[i+1]);
  }
  r += TriS(p, input[0], input[n-1]);
  return r;
}

int main()
{
  ifstream cin("video.txt");
  for(int iii = 1; cin >> n; ++iii) {
    if(n == 0)
      break;
    if(iii != 1)
      cout << endl;
    for(int i = 0; i < n; ++i)
      cin >> input[i].x >> input[i].y;
    int s = TruePoriS();
    bool ok = true;
    for(int i = 1; i < n; ++i) {
      if(s != PoriS(input[i])) {
	ok = false;
	break;
      }
    }
    cout << "Floor #" << iii << endl;
    if(ok)
      cout << "Surveillance is possible." << endl;
    else
      cout << "Surveillance is impossible." << endl;
  }
}