Bingo

Point p[MAX_N];
Line l[MAX_N];
Point pp[MAX_N];
int n,nP;

int main()
{
    int i,j,tmp;
    int ans,Case;
    Case = 1;
    while(scanf("%d",&n),n)
    {
        for(i=0;i<n;i++)
        {
            scanf("%lf%lf",&p[i].x,&p[i].y);
        }
        //p[n] = p[0];
        for(i=0;i<n-1;i++)
        {
            l[i].p1 = p[i];
            l[i].p2 = p[i+1];
        }
        ans = 0;
        for(i=0;i<n-1;i++)
        {
            nP = 0;
            for(j=0;j<i;j++)
            {
                if(LineSegIntersect(l[i],l[j]))
                {
                    Point tmpP;
                    if(CalCrossPoint(l[i],l[j],tmpP)==COLINE)
                    {
                        if(l[i].p1 == l[j].p2 || l[i].p1 == l[j].p1) continue;
                        else tmpP = l[i].p2;
                    }
                    if(tmpP == l[i].p1) continue;
                    pp[nP++] = tmpP;
                }
            }
            sort(pp,pp+nP,cmp);
            ans += nP;
            for(j=1;j<nP;j++)
            {
                if(pp[j] == pp[j-1])
                {
                    ans--;
                }
            }
        }
        printf("Case %d: There are %d pieces.\n",Case++,ans+1);
    }
    return 0;
}