#include<cmath>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 #define FOR(a,b,c) for(int a=(b);a<(c);a++)

 using namespace std;

 const double eps = 1e-;

 int dcmp(double x) {

     if(fabs(x)<eps) return ; else return x<? -:;

 }

 struct Pt {

     double x,y;

     Pt(double x=,double y=):x(x),y(y) {};

 };

 typedef Pt vec;

 vec operator - (Pt A,Pt B) { return vec(A.x-B.x,A.y-B.y); }

 vec operator + (vec A,vec B) { return vec(A.x+B.x,A.y+B.y); }

 vec operator * (vec A,double p) { return vec(A.x*p,A.y*p); }

 double Dot(vec A,vec B) { return A.x*B.x+A.y*B.y; }

 double cross(vec A,vec B) { return A.x*B.y-A.y*B.x; }

 bool operator < (const Pt& a,const Pt& b) {

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

 }

 bool operator == (const Pt& a,const Pt& b) {                // for unique

     return dcmp(a.x-b.x)== && dcmp(a.y-b.y)==;

 }

 Pt LineIntersection(Pt P,vec v,Pt Q,vec w) {

     vec u=P-Q;

     double t=cross(w,u)/cross(v,w);

     return P+v*t;

 }

 bool SegIntersection(Pt a1,Pt a2,Pt b1,Pt b2) {

     double c1=cross(a2-a1,b1-a1) , c2=cross(a2-a1,b2-a1) ,

            c3=cross(b2-b1,a1-b1) , c4=cross(b2-b1,a2-b1);

     return dcmp(c1)*dcmp(c2)< && dcmp(c3)*dcmp(c4)<;

     // b1 b2在线段a1a2的两侧  a1 a2在线段b1b2的两侧 => 规范相交

 }

 bool OnSeg(Pt P,Pt a1,Pt a2) {

     return dcmp(cross(a1-P,a2-P))== && dcmp(Dot(a1-P,a2-P))<;

 }

 const int N = +;

 Pt P[N],V[N*N];

 int n;

 int main() {

     int kase=;

     while(scanf("%d",&n)== && n) {

         FOR(i,,n)

             scanf("%lf%lf",&P[i].x,&P[i].y) , V[i]=P[i];

         n--;

         int c=n,e=n;

         FOR(i,,n) FOR(j,i+,n)

             if(SegIntersection(P[i],P[i+],P[j],P[j+]))

                 V[c++]=LineIntersection(P[i],P[i+]-P[i],P[j],P[j+]-P[j]);

         sort(V,V+c);

         c=unique(V,V+c)-V;

         FOR(i,,c) FOR(j,,n)

             if(OnSeg(V[i],P[j],P[j+])) e++;

         printf("Case %d: There are %d pieces.\n",++kase,e+-c);

     }

     return ;

 }