/* @JUDGE_ID: 32472GK 1034 C++ */
#include <iostream>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <map>
#include <algorithm>
#include <climits>
#include <cctype>
#include <cassert>
using namespace std;

typedef pair<int, int> point;

bool is_safe(vector<pair<int, int> >& q, int N)
{
  vector<int> ng1(2 * N - 1);
  vector<int> ng2(2 * N - 1);

  for (int i = 0; i < N; ++i) {
    int idx1 = q[i].first + q[i].second;
    int idx2 = q[i].first + (N - q[i].second - 1);
    if (ng1[idx1] || ng2[idx2]) { return false; }
    ng1[idx1] = ng2[idx2] = true;
  }

  return true;
}

int solve(vector<pair<int, int> >& q, int N)
{
  if (N < 3) { return 0; }
  int cnt = 0;
  
  for (int i = 0; i < N; ++i) {
    for (int j = i + 1; j < N; ++j) {
      for (int k = j + 1; k < N; ++k) {
        int xs[] = { q[i].first, q[j].first, q[k].first };
        int ys[] = { q[i].second, q[j].second, q[k].second };

        q[i] = point(xs[0], ys[1]);
        q[j] = point(xs[1], ys[2]);
        q[k] = point(xs[2], ys[0]);
        if (is_safe(q, N)) { ++cnt; }

        q[i] = point(xs[0], ys[2]);
        q[j] = point(xs[1], ys[0]);
        q[k] = point(xs[2], ys[1]);
        if (is_safe(q, N)) { ++cnt; }

        q[i] = point(xs[0], ys[0]);
        q[j] = point(xs[1], ys[1]);
        q[k] = point(xs[2], ys[2]);
      }
    }
  }

  return cnt;
}

int main()
{
  int N; cin >> N;
  vector<point> queens(N);
  for (int i = 0; i < N; ++i) {
    int x, y; cin >> x >> y;
    queens[i] = point(x-1, y-1);
  }
  sort(queens.begin(), queens.end());
  cout << solve(queens, N) << endl;
}