#include <cstdio>
#include <cmath>
#include <vector>
#include <algorithm>
using namespace std;

int n,d;
int x[1000],y[1000];
double pos[1000];
int cov[1000];

double sqr(double x) {
	return x*x;
}

double dist2(int i, double p) {
	return sqr(x[i]-p)+sqr(y[i]);
}

int main() {
	for (int t=1;;t++) {
		scanf("%d %d",&n,&d);
		if (n==0 && d==0) break;
		int ok=1;
		for (int i=0;i<n;i++) {
			scanf("%d %d",&x[i],&y[i]);
			cov[i]=0;
			if (y[i]>d) ok=0;
			pos[i]=x[i]+sqrt(sqr(d)-sqr(y[i]));
		}
		printf("Case %d: ",t);
		if (!ok) {
			printf("%d\n",-1);
			continue;
		}
		int st=0;
		while (1) {
			double mp=0;
			int found=0;
			for (int i=0;i<n;i++) if (!cov[i]) {
				if (!found) {
					mp=pos[i];
					found=1;
				}
				mp=min(mp,pos[i]);
			}
			if (!found) break;
			st++;
			for (int i=0;i<n;i++) if (!cov[i]) {
				if (dist2(i,mp)<=sqr(d)+1e-9) cov[i]=1;
			}
		}
		printf("%d\n",st);
	}
	return 0;
}