#include <cassert>
#include <functional>
#include <set>
#include <ctime>
#include <cmath>
#include <climits>
#include <string>
#include <queue>
#include <map>
#include <vector>
#include <algorithm>
#include <iostream>
#include <cstdio>
#ifndef ONLINE_JUDGE //POJ
# include <random>
# include <array>
# define mkt make_tuple
# define empb emplace_back
#endif
#ifdef _LOCAL
# include "for_local.h"
#endif
using namespace std;
typedef unsigned int uint; typedef unsigned long long ull;
#define repi(_I, _B, _E) for(int _I = (_B); (_I) < (_E); ++ (_I))
#define rep(_I, _N) for(int _I = 0; (_I) < (_N); ++ (_I))
#define mkp make_pair
#define all(_X) (_X).begin(), (_X).end()
#define scani(_V) std::scanf("%d", &_V)
#define printi(_V) std::printf("%d", static_cast<int>(_V))

#include <list>
template<typename T>
T selfprod(T const& x, T const& y) { return x * x + y * y; }

int const INF = 1 << 29;
int const B = 40; //bucket size
vector<vector<pair<int,int>>> bs(20001 / B + 1);
bool conflict(int i, int x, int y) {
	if ( !(0 <= i && i < bs.size()) ) return false;
	auto& b = bs[i];
	auto lb = lower_bound(all(b), mkp(x - 20, 0));
	auto ub = upper_bound(all(b), mkp(x + 20, INF));
	for ( ; lb != ub; ++lb ) {
		auto& p = *lb;
		if ( selfprod(x - p.first, y - p.second) < 400 ) return true;
	}
	return false;
}
bool conflict(int x, int y) {
	int yl = max((y - 20) / B, 0);
	int yr = min((y + 20 + B - 1) / B, (int)bs.size());
	//assert(yr - yl <= 2);
	for ( int i = yl; i < yr; ++i ) {
		if ( conflict(i, x, y) ) return true;
	}
	return false;
}

signed main() {
	int n;
	scanf("%d", &n);

	int k = 0;
	rep(i, n) {
		int x, y;
		scanf("%d %d", &x, &y);
		if ( !conflict(x, y) ) {
			//bs[i]: y座標が [i*B, (i+1)*B) に入る点全体をもつ。x座標について整列済み。
			bs[y / B].emplace(lower_bound(all(bs[y / B]), mkp(x, y)), mkp(x, y));
			++k;
		}
	}
	printf("%d\n", k);
	return 0;
}