#include <string>
#include <vector>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<stack>
#include<queue>
#include<cmath>
#include<algorithm>
#include<functional>
#include<list>
#include<deque>
#include<bitset>
#include<set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<sstream>
#include<complex>
#include<iomanip>
#include<numeric>
#define X first
#define Y second
#define pb push_back
#define rep(X,Y) for (int (X) = 0;(X) < (Y);++(X))
#define rrep(X,Y) for (int (X) = (Y-1);(X) >=0;--(X))
#define repe(X,Y) for ((X) = 0;(X) < (Y);++(X))
#define peat(X,Y) for (;(X) < (Y);++(X))
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<class T> using vv=vector<vector<T>>;
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"{"; rep(i,t.size()) {os<<t[i]<<",";} os<<"}"<<endl; return os;}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}

int ex[2100][2100],ey[2100][2100];

int fun(int x,int y){return x*x+y*y;}

int main(){
  ios_base::sync_with_stdio(false);
  cout<<fixed<<setprecision(0);
  int i,j,k,n,re=0,x,y;
  fill(ex[0],ex[0]+2100*2100,-1);
  cin>>n;
  rep(hoge,n){
    //rep(i,10){rep(j,10)cout<<pii(ex[i][j],ey[i][j])<<",";cout<<endl;}
    cin>>x>>y;
    int f=0;
    for(int i=max(0,y/10-2);i<=min(2099,y/10+2);++i)
      for(int j=max(0,x/10-2);j<=min(2099,x/10+2);++j)
	if(ex[i][j]>=0 && fun(x-ex[i][j],y-ey[i][j])<400)
	  f=1;
    //cout<<x<<","<<y<<":"<<f<<endl;
    if(f)continue;
    ex[y/10][x/10]=x; ey[y/10][x/10]=y;
    ++re;
  }
  cout<<re<<endl;
  return 0;
}