Time limit : 1 sMemory limit : 32 mb
Submitted : 1336Accepted : 408

### Problem Description

Assume the coasting is an infinite straight line. Land is in one side of coasting, sea in the other. Each small island is a point locating in the sea side. And any radar installation, locating on the coasting, can only cover d distance, so an island in the sea can be covered by a radius installation, if the distance between them is at most d.

We use Cartesian coordinate system, defining the coasting is the x-axis. The sea side is above x-axis, and the land side below. Given the position of each island in the sea, and given the distance of the coverage of the radar installation, your task is to write a program to find the minimal number of radar installations to cover all the islands. Note that the position of an island is represented by its x-y coordinates.

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### Input

The input is terminated by a line containing pair of zeros.

### Output

For each test case output one line consisting of the test case number followed by the minimal number of radar installations needed. "-1" installation means no solution for that case.

### Sample Input

3 2
1 2
-3 1
2 1

1 2
0 2

0 0


### Sample Output

Case 1: 2
Case 2: 1