POJ 1328

#include <iostream>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
#include <map>
#include <iomanip>
#include <algorithm>
#include <queue>
#include <stack>
#include <set>
#include <vector>
//const int maxn = 1e5+5;
#define ll long long
#define MAX INT_MAX
#define FOR(i,a,b) for( int i = a;i <= b;++i)
using namespace std;
struct node
{
    double x,y,l,r;
}v[1100];
bool cmp(node a,node b)
{
    return a.l<b.l;
}
int n,d,ans,k;
int hhh;
double dl,dr;
int main()
{
    while(scanf("%d %d",&n,&d)&&n&&d)
    {
        hhh=0;
        k++;
        memset(v,0,sizeof(v) );
        ans=0;
        FOR(i,1,n)
        {
            cin>>v[i].x>>v[i].y;
            if(v[i].y>d)
            {
                 hhh=1;
            }
        }
        if(hhh==1)
        {
            printf("Case %d: -1\n", k);
        }
        else
        {
            FOR(i,1,n)
            {
                v[i].l=v[i].x-sqrt(d*d-v[i].y*v[i].y);
                v[i].r=v[i].x+sqrt(d*d-v[i].y*v[i].y);
            }

            sort(v+1,v+n+1,cmp);

            double dl=v[1].l,dr=v[1].r;
            ans=1;


            for(int i=2;i<=n;++i)
            {
                if(v[i].l>dr)            //可以覆盖这个点
                {
                   // dr=max(v[i].r,dr);
                   dr=v[i].r;
                   ans++;
                }
                else if(v[i].r<dr)
                {
                    dr=v[i].r;
                }
            }
            printf("Case %d: %d\n", k,ans);
        }

    }


    /*FOR(i,1,n)
    {
        cout<<v[i].l<<" "<<v[i].r<<endl;
    }*/

}