#include <bits/stdc++.h>

using namespace std;

#define eps 1e-8

const double pi=acos(-1);

struct Point

{

    double x,y;

    Point(double a=0,double b=0)

    {

        x=a;

        y=b;

    }

};

Point operator - (Point a,Point b)

{

    return Point(a.x-b.x,a.y-b.y);

}

double dist(Point a,Point b)

{

    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));

}

double multi(Point a,Point b)

{

    return a.x*b.x+a.y*b.y;

}

double cross(Point a,Point b)

{

    return a.x*b.y-a.y*b.x;

}

Point TriangleCircumCenter(Point a,Point b,Point c)

{

    Point res;

    double a1=atan2(b.y-a.y,b.x-a.x)+pi/2;

    double a2=atan2(c.y-b.y,c.x-b.x)+pi/2;

    double ax=(a.x+b.x)/2;

    double ay=(a.y+b.y)/2;

    double bx=(c.x+b.x)/2;

    double by=(c.y+b.y)/2;

    double r1=(sin(a2)*(ax-bx)+cos(a2)*(by-ay))/(sin(a1)*cos(a2)-sin(a2)*cos(a1));

    return Point(ax+r1*cos(a1),ay+r1*sin(a1));

}

int main()

{

//    freopen("in.txt","r",stdin);

//    freopen("out.txt","w",stdout);

    int x1,y1,x2,y2,x3,y3,xp,yp;

    int kase=0;

    while(~scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3,&xp,&yp))

    {

        Point p1=Point(x1,y1);

        Point p2=Point(x2,y2);

        Point p3=Point(x3,y3);

        Point pp=Point(xp,yp);

        Point pc=TriangleCircumCenter(p1,p2,p3);    //算圆心

        double temp=cross(p2-p1,p3-p1);

        if(temp<0)  //如果是顺时针，把p1和p3点互换

        {

            Point t=p1;

            p1=p3;

            p3=t;

        }

        double cosA=multi(p1-pc,p3-pc)/(dist(p1,pc)*dist(p3,pc));

        if(fabs(cosA)>1)    //如果fabs(cosA)>1，那么acos(cosA)算出的结果是不合法的

        {

            if(cosA<0) cosA+=eps;

            else cosA-=eps;

        }

        double maxd=acos(cosA); //算p1-pc与p3-pc的夹角

        if(cross(p1-pc,p3-pc)<0 && fabs(cross(p1-pc,p3-pc))>eps)

            maxd=2*pi-maxd;

        double cosB=multi(p1-pc,pp-pc)/(dist(p1,pc)*dist(pp,pc));

        if(fabs(cosB)>1)

        {

            if(cosB<0) cosB+=eps;

            else cosB-=eps;

        }

        double degree=acos(cosB);   //算p1-pc与pp-pc的夹角

        if(cross(p1-pc,pp-pc)<0 && fabs(cross(p1-pc,pp-pc))>eps)

            degree=2*pi-degree;

        if(degree<maxd)

            printf("Case %d: %.3lf\n",++kase,fabs(dist(pp,pc)-dist(p1,pc)));

        else

            printf("Case %d: %.3lf\n",++kase,min(dist(pp,p1),dist(pp,p3)));

    }

    return 0;

}