#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <numeric>
#define rep(x, to) for (int x = 0; x < (to); x++)
#define REP(x, a, to) for (int x = (a); x < (to); x++)
#define foreach(itr, x) for (typeof((x).begin()) itr = (x).begin(); itr != (x).end(); itr++)
#define sq(x) ((x) * (x))

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;
typedef pair<long, long> PLL;

const int BOX_N = 205;

int N;
int X[100005];
int Y[100005];

vector< vector< vector<PII> > > box(BOX_N);

int ans;

int mx[] = {1, 1, 0, -1, -1, -1, 0, 1};
int my[] = {0, 1, 1,  1,  0, -1,-1,-1};

int dist(PII a, PII b) {
	return sq(a.first - b.first) + sq(a.second - b.second);
}

void solve(int x, int y) {
	int bx = x / 100;
	int by = y / 100;
	bool add = true;
	//着目
	{
		rep(i, box[by][bx].size()) {
			if (dist(box[by][bx][i], PII(y, x)) < 400) {
				add = false;
			}
		}
	}
	//着目近傍
	rep(k, 8) {
		int nx = bx + mx[k];
		int ny = by + my[k];
		if (nx < 0 || ny < 0) continue;
		rep(i, box[ny][nx].size()) {
			if (dist(box[ny][nx][i], PII(y, x)) < 400) {
				add = false;
			}
		}
	}
	if (add) {
		box[by][bx].push_back(PII(y, x));
		ans++;
	}
}

int main() {
	rep(i, BOX_N) box[i].resize(BOX_N);
	cin >> N;
	rep(i, N) {
		cin >> X[i] >> Y[i];
		solve(X[i], Y[i]);
	}
	cout << ans << endl;
	return 0;
}