#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>


using namespace std;

double other_leg(const double leg, const double diag) {
    return sqrt(diag * diag - leg * leg);
}

double diag(const double leg1, const double leg2) {
    return sqrt(leg1 * leg1 + leg2 * leg2);
}

int required_radars(vector<pair<int, int>> islands, int distance) {
    for (auto& [island_x, island_y] : islands) {
        if (island_y > distance) { return -1; }
    }
    sort(islands.begin(), islands.end());
    int answer = 0;
    while (!islands.empty()) {
        answer++;
        const auto current_island = islands.back();
        islands.pop_back();
        double min_x = current_island.first
            - other_leg(current_island.second, distance)
            - current_island.second;
        vector<pair<int, int>> uncovered_islands;
        while (!islands.empty() && islands.back().first >= min_x) {
            // 右移雷达
            const double offset = other_leg(islands.back().second, distance);
            if (islands.back().first - offset >= min_x) {
                min_x = islands.back().first - offset;
            } else {
                uncovered_islands.push_back(islands.back());
            }
            islands.pop_back();
        }
        for (int i = uncovered_islands.size() - 1; i >= 0; i--) { // NOLINT(*-narrowing-conversions)
            islands.push_back(uncovered_islands[i]);
        }
    }
    return answer;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, distance, case_id = 0;
    while (cin >> n >> distance) {
        if (n == 0 && distance == 0) { break; }
        vector<pair<int, int>> islands(n);
        for (int i = 0; i < n; i++) {
            cin >> islands[i].first >> islands[i].second;
        }
        cout << "Case " << ++case_id << ": " << required_radars(islands, distance) << endl;
    }
}