#include"iostream"
#include"cmath"
using namespace std;
struct Point
{
	double  left;
	double  right;
}island;


/*int cmp( const void *a , const void *b )
{

     Point *c = (Point *)a;

     Point *d = (Point *)b;

    if(c->left != d->left)  return c->left- d->left;

    else return d->right - c->right;
}*/
int cmp(const void *p1, const void *p2) 
{ 
   Point I1 = *(Point *)p1; 
   Point I2 = *(Point *)p2; 
   double temp = I1.left - I2.left; 
   if (temp > 0.0) return 1; 
   else if (temp < 0.0) return -1; 
   else { 
      temp = I2.right - I1.right; 
      if (temp > 0.0) return 1; 
      else return -1; 
   } 
} 

int main()
{
	
	Point island[1005]; 
    int n,d,x[1005],y[1005],i,dd,count,flag;

	int num=0;
    double sqrtdy,right;

	while(cin>>n>>d)
	{
		num++;
		int flag=0;
		if(n==0&&d==0)
			break;
		
	    for( i=0;i<n;i++)
		{
		   cin>>x[i]>>y[i];
		   if(y[i]>d)
		       flag=1;
		}
	       
		
		if(flag==1)
		{
        cout<<"Case "<<num<<": "<<-1<<endl;
			continue;
		}
       dd=d*d;
       for (i = 0; i < n; i++)
	   { 
         sqrtdy = sqrt((double)(dd - y[i]*y[i])); 
         island[i].left=x[i]-sqrtdy; 
         island[i].right=x[i]+sqrtdy; 
		 
      } 
		
		qsort(island,n,sizeof(Point),cmp);
		right=island[0].right;
		count=1;
		for( int j=1;j<n;j++)
		{
			if(island[j].left>right)
			{
				count++;
				right=island[j].right;
			}
			else
			{
				
				if(island[j].right<right)
				{
				   right=island[j].right;
				}
			}
		}
		cout<<"Case "<<num<<": "<<count<<endl;
	

	}
	return 1;
}

        
/*
int main()
{
    Point points[1005]; 

    int n,d,x[1005],y[1005],i,dd,cnt,flag;
    int t=0;
    double sqrtdy,right;
    
    while(scanf("%d%d",&n,&d)&&!(n==0&&d==0))
    {
      t++;
      flag=0;
	  int i;
      for(i=0;i<n;i++)
      {
       scanf("%d%d",&x[i],&y[i]);
       if(y[i]>d) flag=1;
       }
      if(flag) 
      {  
         printf("Case %d: %d\n",t, -1); 
         continue; 
      } 
      
      dd=d*d;
      for (i = 0; i < n; i++)
       { 
         sqrtdy = sqrt((double)(dd - y[i]*y[i])); 
         points[i].left = x[i]-sqrtdy; 
         points[i].right =x[i]+ sqrtdy; 
      } 

      
      qsort(points,n,sizeof(Point),cmp);
      
     
      
      cnt=1;
      right=points[0].right;
      for(i=1;i<n;i++)
      {
        if(points[i].left>right)
        {
         cnt++;
         right=points[i].right;
        }
        else { 
            if (points[i].right < right) 
               right = points[i].right; 
         } 
      }
      
    printf("Case %d: %d\n",t,cnt); 
      
    }
    
}*/