#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>
#include<cstring>
#include<vector>
#include<list>
#include<algorithm>
#include<map>
#include<set>
#include<queue>
#include<stack>
using namespace std;
typedef long long ll;
#define fi first
#define se second
#define mp make_pair
#define mt make_tuple
#define pqueue priority_queue
const int inf=1e9+7;
const ll mod=1e9+7;
const ll mod1=998244353;
const ll big=1e18;
const double PI=2*asin(1);

int main() {
  int N;
  cin>>N;
  ll x[N], y[N];
  for(int i=0;i<N;++i) cin>>x[i]>>y[i];
  priority_queue<tuple<ll, int, int>, vector<tuple<ll, int, int> >, greater<tuple<ll, int, int> > > que;
  for(int i=0;i<N;++i) {
    for(int j=0;j<N;++j) {
      if(i==j) continue;
      que.push(mt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]), i, j));
    }
  }
  map<int, int> amap;
  int ans = 0;
  tuple<ll, int, int> state;
  int x1, y1;
  while(!que.empty()) {
    state = que.top();que.pop();
    x1 = get<1>(state);
    y1 = get<2>(state);
    if(amap[x1]>0 || amap[y1]>0) continue;
    if(x1==0 || y1==0) ans++;
    if(x1!=0) amap[x1]++;
    if(y1!=0) amap[y1]++;
  }
  cout<<ans<<endl;
}