#include<iostream>

#include<string.h>

#include<stdio.h>

#include<algorithm>

#include<math.h>

#include<queue>

using namespace std;

const int MAXN = ;

const int oo = 1e9+;

const double EPS = 1e-;

int Sign(double t)

{

    if(t > EPS)

        return ;

    if(fabs(t) < EPS)

        return ;

    return -;

}

struct Point

{

    double  x, y;

    Point(double x=, double y=):x(x),y(y){}

    Point operator - (const Point &t)const{

        return Point(x-t.x, y-t.y);

    }

    double operator ^(const Point &t)const{

        return x*t.y - y*t.x;

    }

}p[MAXN], in[MAXN];

struct Segment

{

    Point S, E;

    double a, b, c;

    Segment(Point S=, Point E=):S(S), E(E){

        a = S.y - E.y;

        b = E.x - S.x;

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

    }

    Point crossNode(const Segment &t)const{

        Point res;

        res.x = (c*t.b-t.c*b) / (a*t.b-t.a*b);

        res.y = (c*t.a-t.c*a) / (b*t.a-t.b*a);

        return res;

    }

    int Mul(const Point &t)

    {///用叉积判断方向

        return Sign((E-S)^(t-S));

    }

};

int CutPoly(Segment L, int N)

{

    Point tmp[MAXN];

    int cnt = ;

    for(int i=; i<=N; i++)

    {

        if(L.Mul(in[i]) <= )

            tmp[++cnt] = in[i];

        else

        {

            if(L.Mul(in[i-]) < )///求出交点

                tmp[++cnt] = L.crossNode(Segment(in[i-],in[i]));

            if(L.Mul(in[i+]) < )

                tmp[++cnt] = L.crossNode(Segment(in[i],in[i+]));

        }

    }

    for(int i=; i<=cnt; i++)

        in[i] = tmp[i];

    in[] = in[cnt], in[cnt+] = in[];

    return cnt;

}

int main()

{

    int N, t=;

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

    {

        int M;

        double s=;

        for(int i=; i<=N; i++)

        {

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

            in[i] = p[i];

            if(i != )

                s += p[i].x*p[i-].y - p[i].y*p[i-].x;

        }

        s += p[].x*p[N].y - p[].y*p[N].x;

        if(s < )

        {

            for(int i=; i<=N/; i++)

            {

                swap(p[i], p[N-i+]);

                swap(in[i], in[N-i+]);

            }

        }

        in[] = p[] = p[N];

        in[N+] = p[N+] = p[];

        M = N;

        for(int i=; i<=N; i++)

            M = CutPoly(Segment(p[i],p[i+]), M);

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

        if(M > )

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

        else

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

    }

    return ;

}