#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using ll = long long;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

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

    int N;
    cin >> N;
    vector<int> X(N), Y(N);
    for(int i = 0; i < N; ++i)  cin >> X[i] >> Y[i];

    vector<set<int>> ys(20001);
    for(int i = 0; i <= 20000; ++i){
        ys[i].emplace(-1000);
        ys[i].emplace(21000);
    }
    
    int ans = 0;
    for(int i = 0; i < N; ++i){
        bool ok = true;
        for(int x = max(0, X[i] - 19); x <= min(20000, X[i] + 19); ++x){
            int dx = X[i] - x;
            int lb = -1000, ub = Y[i];
            while(ub - lb > 1){
                int mid = (lb + ub) / 2;
                int dy = abs(mid - Y[i]);
                if(dx * dx + dy * dy >= 400)    lb = mid;
                else    ub = mid;
            }
            int low = lb;
            lb = Y[i], ub = 21000;
            while(ub - lb > 1){
                int mid = (lb + ub) / 2;
                int dy = abs(mid - Y[i]);
                if(dx * dx + dy * dy >= 400)    ub = mid;
                else    lb = mid;
            }
            int high = ub;
            if(*ys[x].lower_bound(low) < high){
                ok = false;
                break;
            }
        }
        if(ok){
            ys[X[i]].emplace(Y[i]);
            ans += 1;
        }
    }

    cout << ans << endl;

    return 0;
}