#include <algorithm>
#include <bitset>
#include <chrono>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using ll = long long;
using vll = std::vector<ll>;
using namespace std;
#define REP(i, x, n) for(int i = x; i < (n); i++)
#define rep(i, n) REP(i, 0, n)
const ll MOD = 1000000007;
template<class T> void gi(T &x){
  int minus=0; x=0; char c=getchar();
  for(;c<'0'||c>'9'; c=getchar()) minus|=(c=='-');
  for(;c>='0'&&c<='9'; c=getchar()) x=(x<<1)+(x<<3)+(c^48);
  if(minus) x=-x;
}
int main() {
  int n; gi(n);
  vector<pair<int,int>> xy;
  rep(i,n){
    int x,y; gi(x);gi(y);
    xy.push_back({x,y});
  }
  vector<bool> chk(n);
  REP(i,1,n){
    if(chk[i]) continue;
    double d0 = sqrt((xy[0].first-xy[i].first)*(xy[0].first-xy[i].first)
      +(xy[0].second-xy[i].second)*(xy[0].second-xy[i].second));
    REP(j,i+1,n){
      if(chk[j]) continue;
      double d = sqrt((xy[j].first-xy[i].first)*(xy[j].first-xy[i].first)
      +(xy[j].second-xy[i].second)*(xy[j].second-xy[i].second));
      if(d < d0){
        chk[i] = true;
        chk[j] = true;
        break;
      }
    }
  }
  int cnt=0;
  REP(i,1,n){
    if(chk[i]==false) cnt++;
  }
  printf( "%d\n", cnt );
  return 0;
}