> #include <cmath>
> #include <cstdio>
> #include <cstdlib>
> #include <iostream>            //哪里错了！！
> 
> using namespace std;
> 
> const int maxn =  1000;
> struct Point
> {
>     double l, r;
>     int x, y;
> } line[maxn];
> int cmp(const void *a, const void *b)
> {
>     return (*(Point*)a).x > (*(Point*)b).x;
> }
> int main()
> {
>     int n, d;
>     int t=0;
>     while(cin >> n >> d && (n!=0 || d!=0))
>     {
>         t++;
>         int flag=1;
>         int ans = 0;
>         for(int i=0; i<n; i++)
>         {
>             scanf("%d%d", &line[i].x, &line[i].y);
>             if(line[i].y>d ||d<0) flag=0;
>         }
>         if(flag)
>         {
>             qsort(line, n, sizeof(line[0]), cmp);
>             for(int i=0; i<n; i++)
>             {
>                 double xx = (double)sqrt((double)d*d-line[i].y*line[i].y);
>                 line[i].l = line[i].x-xx;
>                 line[i].r = line[i].x+xx;
>             }
>             double now=line[0].r;
> 
>             ans++;
>             for(int i=1; i<n; i++)
>             {
>                 // printf("\n ans= %d now = %lf line[i].l=%lf \n", ans, now, line[i].l);
>                 if(now>line[i].r) { now=line[i].r;}
>                 else if(now<line[i].l)
>                 {
>                     ans++;
>                     now=line[i].r;
>                 }
>             }
>         }
>         else ans=-1;
>         printf("Case %d: %d\n\n", t, ans);
>     }
> }