#include <cstdio>

 #include <cstring>

 #include <string>

 #include <cmath>

 #include <algorithm>

 using namespace std;

 #define eps 1e-8

 #define N 2001

 struct point

 {

     double x,y;

 }p[N],pre[N],temp[N];

 double a,b,c;

 int n,m;

 void getline(point x,point y)

 {

     a = y.y - x.y;

     b = x.x - y.x;

     c = y.x * x.y - x.x * y.y;

 }

 point intersect(point x,point y)

 {

     double u = fabs(a*x.x + b*x.y + c);

     double v = fabs(a*y.x + b*y.y + c);

     point ans;

     ans.x = (x.x*v+y.x*u)/(u+v);

     ans.y = (x.y*v+y.y*u)/(u+v);

     return ans;

 }

 void cut()

 {

     int num = ,i;

     for(i = ;i <= m;i ++)

     {

         if(a*p[i].x + b*p[i].y + c > -eps)

         {

             temp[++num] = p[i];

         }

         else

         {

             if(a*p[i-].x + b*p[i-].y + c > eps)

             temp[++num] = intersect(p[i],p[i-]);

             if(a*p[i+].x + b*p[i+].y + c > eps)

             temp[++num] = intersect(p[i],p[i+]);

         }

     }

     for(i = ;i <= num;i ++)

     p[i] = temp[i];

     p[] = p[num];

     p[num+] = p[];

     m = num;

 }

 void fun()

 {

     int i;

     m = n;

     for(i = ;i <= n;i ++)

     {

         getline(pre[i],pre[i+]);

         cut();

     }

 }

 int main()

 {

     int i,cas = ;

     while(scanf("%d",&n)!=EOF)

     {

         if(!n) break;

         for(i = ;i <= n;i ++)

         {

             scanf("%lf%lf",&pre[i].x,&pre[i].y);

             p[i] = pre[i];

         }

         pre[n+] = pre[];

         p[n+] = p[];

         p[] = p[n];

         fun();

         printf("Floor #%d\n",cas ++);

         if(m)

         printf("Surveillance is possible.\n");

         else

         printf("Surveillance is impossible.\n");

         printf("\n");

     }

     return ;

 }