# include <stdio.h>
# include <algorithm>
# include <string.h>
# include <math.h>
using namespace std;
struct point
{
	double left,right;
}p[2010],temp;
bool cmp(point a,point b)
{
	return a.left<b.left;
}
int  main()
{
	int n,i,count,flag,cas=0;
	double r,a,b;
	while(~scanf("%d%lf",&n,&r),n+r)
	{
		flag=0;
		for(i=0;i<n;i++)
		{

			scanf("%lf %lf",&a,&b);
			if(fabs(b)>r)
				flag=true;
			else
			{
				p[i].left=a*1.0-sqrt(r*r-b*b);
				p[i].right=a*1.0+sqrt(r*r-b*b);
			}
		}
		printf("Case %d: ",++cas);
		if(flag)
			printf("-1\n");
		else
		{
			sort(p,p+n,cmp);
			count=1;
			temp=p[0];
			for(i=1;i<n;i++)
			{
				if(p[i].left>temp.right)
				{
					count++;
					temp=p[i];
				}
				else if(p[i].right<temp.right)//
					temp=p[i];
			}
			printf("%d\n",count);
		}
	}
	return 0;
}