#define _CRT_SECURE_NO_WARNINGS
//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
//#define int ll
//#define endl "\n"
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
#define all(c) (c).begin(), (c).end()
#define loop(i,a,b) for(ll i=a; i<ll(b); i++)
#define rep(i,b) loop(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
template<class T> ostream & operator<<(ostream & os, vector<T> const &);
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":" ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream & os, tuple<T...> const & t){ _ot<0>(os, t); return os; }
template<class T, class U> ostream & operator<<(ostream & os, pair<T,U> const & p){ return os << "(" << p.first << ", " << p.second << ") "; }
template<class T> ostream & operator<<(ostream & os, vector<T> const & v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; }
template<class T> inline bool chmax(T & x, T const & y){ return x<y ? x=y,true : false; }
template<class T> inline bool chmin(T & x, T const & y){ return x>y ? x=y,true : false; }
#ifdef DEBUG
#define dump(...) (cerr<<#__VA_ARGS__<<" = "<<mt(__VA_ARGS__)<<" ["<<__LINE__<<"]"<<endl)
#else
#define dump(...)
#endif
// ll const mod = 1000000007;
// ll const inf = 1LL<<60;

int N;
int const l = 80;
vector<pair<int,int>> baq[20010/l][200010/l];

bool check(int x, int y){
    int bx = x/l, by = y/l;
    for(int i=by-1;i<=by+1;i++){
        for(int j=bx-1;j<=bx+1;j++){
            for(auto & p : baq[i][j]){
                int cx, cy;
                tie(cx,cy) = p;
                int dx = x-cx, dy = y-cy;
                int d2 = dx*dx + dy*dy;
                if(d2 < 400) return false;
            }
        }
    }
    return true;
}

int main(){
    cin >> N;
    int ans = 0;
    assert(1 <= N && N <= 100000);
    rep(i,N){
        int x,y;
        cin >> x >> y;
        assert(0 <= x && x <= 20000);
        assert(0 <= y && y <= 20000);
        // x += l;
        // y += l;
        // if(!check(x,y)) continue;
        // baq[y/l][x/l].eb(x,y);
        // ans++;
    }
    cout << ans << endl;
}