#include <bits/stdc++.h>

using namespace std;

using ll = long long;

constexpr char newl = '\n';

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

    int n;
    cin >> n;

    vector<ll> x(n), y(n);
    for (int i = 0; i < n; i++) {
        cin >> x[i] >> y[i];
    }

    vector<int> ids(n);
    iota(ids.begin(), ids.end(), 0);
    sort(ids.begin(), ids.end(), [&](int i1, int i2){
        return x[i1] < x[i2];
    });

    deque<int> dq;
    for (int i : ids) {
        for (int jj = 0; ;) {
            if (jj >= dq.size()) {
                dq.push_front(i);
                break;
            }
            int& j = dq[jj];

            ll dx = x[i] - x[j];
            if (abs(dx) >= 20) {
                dq.push_front(i);
                break;
            }

            ll dy = y[i] - y[j];
            ll r2 = dx * dx + dy * dy;
            if (r2 >= 400) {
                ++jj;
                continue;
            }

            if (i > j) break;

            swap(j, dq.back());
            dq.pop_back();
        }
    }
    cout << dq.size() << newl;

    return 0;
}