#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  
  using P = pair<Int, Int>;
  set<P> sp;

  vector<P> dz;
  for(Int i=-100;i<=100;i++)
    for(Int j=-100;j<=100;j++)
      if(i*i+j*j<400) dz.emplace_back(i,j);
  
  Int cnt=0;
  for(Int i=0;i<n;i++){
    Int x,y;
    cin>>x>>y;

    Int flg=0;    
    for(auto p:dz)
      flg|=sp.count(P(x+p.first,y+p.second));
      
    if(flg) continue;
    cnt++;
    sp.emplace(x,y);
  }
  
  cout<<cnt<<endl;
  return 0;
}