#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <string>
#include <sstream>
#include <math.h> 

using namespace std;

int main() {
	int caseNum = 1;
	while (true) {
		int n, d;
		cin >> n >> d;
		if (n == 0 && d == 0)
			break;

		bool possible = true;
		vector<pair<double, double>> ranges;
		for (int i = 0; i < n; i++) {
			int x, y;
			cin >> x >> y;
			if (y > d) {
				possible = false;
			}
			ranges.push_back(make_pair(x - sqrt((double)(d * d - y * y)), x + sqrt((double)(d * d - y * y))));
		}

		if (!possible) {
			cout << "Case " << caseNum++ << ": " << -1 << endl;
			continue;
		}

		int ans = 1;
		sort(ranges.begin(), ranges.end());
		double endPoint = ranges[0].second;

		for (int i = 1; i < ranges.size(); i++) {
			if (ranges[i].first > endPoint) {
				ans++;
				endPoint = ranges[i].second;
			} 
			else {
				endPoint = min(endPoint, ranges[i].second);
			}
		}

		cout << "Case " << caseNum++ << ": " << ans << endl;
	}
	return 0;
}