#include <iostream>

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <cmath>

#include <vector>

using namespace std;

typedef long long ll;

const int N=;

const double INF=1e5;

const double eps=1e-;

inline int read(){

    char c=getchar();int x=,f=;

    while(c<''||c>''){if(c=='-')f=-; c=getchar();}

    while(c>=''&&c<=''){x=x*+c-''; c=getchar();}

    return x*f;

}

inline int sgn(double x){

    if(abs(x)<eps) return ;

    else return x<?-:;

}

struct Vector{

    double x,y;

    Vector(double a=,double b=):x(a),y(b){}

    bool operator <(const Vector &a)const{

        return sgn(x-a.x)<||(sgn(x-a.x)==&&sgn(y-a.y)<);

    }

    void print(char c){printf("%c %lf %lf\n",c,x,y);}

};

typedef Vector Point;

Vector operator +(Vector a,Vector b){return Vector(a.x+b.x,a.y+b.y);}

Vector operator -(Vector a,Vector b){return Vector(a.x-b.x,a.y-b.y);}

Vector operator *(Vector a,double b){return Vector(a.x*b,a.y*b);}

Vector operator /(Vector a,double b){return Vector(a.x/b,a.y/b);}

bool operator ==(Vector a,Vector b){return sgn(a.x-b.x)==&&sgn(a.y-b.y)==;}

double Dot(Vector a,Vector b){return a.x*b.x+a.y*b.y;}

double Cross(Vector a,Vector b){return a.x*b.y-a.y*b.x;}

double Len(Vector a){return sqrt(Dot(a,a));}

double DisTL(Point p,Point a,Point b){

    Vector v1=b-a,v2=p-a;

    return abs(Cross(v1,v2)/Len(v1));

}

struct Line{

    Point s,t;

    Line(){}

    Line(Point a,Point b):s(a),t(b){}

};

bool isLSI(Line l1,Line l2){

    Vector v=l1.t-l1.s,u=l2.s-l1.s,w=l2.t-l1.s;

    return sgn(Cross(v,u))!=sgn(Cross(v,w));

}

Point LI(Line a,Line b){

    Vector v=a.s-b.s,v1=a.t-a.s,v2=b.t-b.s;

    double t=Cross(v2,v)/Cross(v1,v2);

    return a.s+v1*t;

}

void iniPolygon(Point p[],int &n,double inf){

    n=;

    p[++n]=Point(-inf,-inf);

    p[++n]=Point(inf,-inf);

    p[++n]=Point(inf,inf);

    p[++n]=Point(-inf,inf);

}

Point t[N];int tn;

void CutPolygon(Point p[],int &n,Point a,Point b){//get the left of a->b

    tn=;

    Point c,d,e;

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

        c=p[i],d=p[i%n+];

        if(sgn(Cross(b-a,c-a))>=) t[++tn]=c;

        if(isLSI(Line(a,b),Line(c,d))){

            e=LI(Line(a,b),Line(c,d));//e.print('e');

            t[++tn]=e;

        }

    }

    n=tn;for(int i=;i<=n;i++)p[i]=t[i];

}

int n,m;

Point p[N],q[N];

int main(int argc, const char * argv[]) {

    int cas=;

    while(true){

        n=read();if(n==) break;

        iniPolygon(q,m,INF);

        for(int i=;i<=n;i++) p[i].x=read(),p[i].y=read();

        for(int i=;i<=n;i++) CutPolygon(q,m,p[i%n+],p[i]);//,printf("%d\n",m);

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

        if(m) puts("Surveillance is possible.\n");

        else puts("Surveillance is impossible.\n");

    }

}