程序代码：

#include<iostream>
#include<cstdio>
#include<math.h>
using namespace std;
int in_circle(double x1,double y1,double r,double x2,double y2)
{
    if(sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))<=r)
    return 1;
    else
    return 0;
}
class circle
{
    public:
     double x;
     double y;
     double r;
};

int main()
{
    int n,i,number,flag;
    int d;
    double x[1010],y[1010];
          int l=1;
         
    while(scanf("%d%d",&n,&d)&&n!=0&&d!=0)
    {
         for(i=0;i<n;i++)
         cin>>x[i]>>y[i];
         for(i=0;i<n;i++)
         {
             for(int j=i+1;j<n;j++)
             {
                 if(y[j]<y[i])
                 {
                     double t=y[i];
                     double k=x[i];
                     y[i]=y[j];
                     x[i]=x[j];
                     y[j]=t;
                     x[j]=k;
                 }
            }
          }  //按y从小到大排序
           if(y[n-1]>d)
           {
               cout<<"Case "<<l<<": -1"<<endl;
               l++;
            }
         
          else
          {
              number=1;
              circle c[100];
              for(int i=0;i<100;i++)
              {
                c[i].y=0;
              c[i].r=d;
              }
              c[0].x=x[n-1];
       
              for(int i=n;i--;i>=0)
              {
                  flag=0;
                  for(int j=0;j<number;j++)
                  {
                      if(in_circle(c[j].x,c[j].y,c[j].r,x[i],y[i]))
                      {
                          flag=1;
                          break;
                      }
                      else
                      continue;
                  }
                  if(flag==0)
                  {
                   number++;
                   c[number-1].x=x[i];
                  }   
            }
            cout<<"Case "<<l<<": "<<number<<endl;
            l++;
          }
           
         
    }
}