#include<bits/stdc++.h>
using namespace std;
int n,d,id,res;
double last=-1e9;
pair<double,double> seg[1010];
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    while(cin>>n>>d){
        id++;
        if(n==0&&d==0) break;
        res=0;
        last=-1e9;
        memset(seg,0,sizeof(seg));
        for(int i=1;i<=n;i++){
            double x,y;
            cin>>x>>y;
            if(y>d){
                cout<<"-1\n";
                return 0;
            }
            seg[i]={x+sqrt(d*d-y*y),x-sqrt(d*d-y*y)};
        }
        sort(seg+1,seg+n+1);
        for(int i=1;i<=n;i++)
            if(seg[i].second>last+1e-6){
                res++;
                last=seg[i].first;
            }
        cout<<"Case "<<id<<": "<<res<<"\n";
    }
    return 0;
}