#include<iostream>

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

using namespace std;

struct dao

{

	double x,y;

}da[10000];

bool cmp(dao a,dao b)

{

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

}

int main()

{

	int n,d;

	double x1,y1;

	int k=0;

	while(~scanf("%d%d",&n,&d)&&(n||d))

	{

		int ans=1;

		for(int i=0;i<n;i++)

		{

			scanf("%lf%lf",&x1,&y1);

			da[i].x=x1-sqrt((double)d*(double)d-(double)y1*y1);

			da[i].y=x1+sqrt((double)d*(double)d-(double)y1*y1);

    		if((d-y1)<0||d<=0) ans=-1;

    	}

		if(ans==-1)

 		{

	 		printf("Case %d: -1\n",++k);

 	 		continue;

		}

  		else

    	{

    		sort(da,da+n,cmp);

    		double t1=da[0].y;

    		for(int i=1;i<n;i++)

        		if(da[i].x>t1)//要是用=号，有些数据不可通过。

        		{

					ans++;

        			t1=da[i].y;//更新右范围

        		}

         	printf("Case %d: %d\n",++k, ans);

    	}

	}

}