#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <functional>
#include <tuple>
#include <climits>
#include <algorithm>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <numeric>
#include <map>
#include <cmath>
#include <cstdlib>
#include <iomanip>

using namespace std;

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

    constexpr int max_x = 20000;
    constexpr int max_y = 20000;
    constexpr int bucket_size = 10;
    using bucket_t = tuple<int, int>;
    enum {
        x = 0,
        y = 1
    };
    map<tuple<int, int>, bucket_t> bucket;
    int count = 0;
    for(int i=0; i<N; i++) {
        bucket_t b = make_tuple(X[i], Y[i]);
        tuple<int, int> bp = make_tuple(X[i]/bucket_size, Y[i]/bucket_size);
        if(bucket.find(bp) != bucket.end()) continue;
        for(int ix=-2; ix<=2; ix++) {
            for(int iy=-2; iy<=2; iy++) {
                tuple<int, int> neighbor = bp;
                get<x>(neighbor) = get<x>(neighbor) + ix;
                get<y>(neighbor) = get<y>(neighbor) + iy;

                if(bucket.find(neighbor) != bucket.end()) {
                    const int squared_distance = pow(get<x>(bucket[neighbor])-get<x>(b), 2) + pow(get<y>(bucket[neighbor])-get<y>(b), 2);
                    if(squared_distance < 400)
                        goto next;
                }
            }
        }
        bucket[bp] = make_tuple(X[i], Y[i]);
        count++;
next:;
    }
    cout << count << endl;
}