#include <iostream>
#include <set>
#include <map>
#include <vector>
#include <algorithm>

using namespace std;

int n;

typedef pair<int,int> position;

bool isBakon(position &p1,position &p2){
  if(p1.first == p2.first) return true;
  if(p1.second == p2.second) return true;
  if(abs(p1.first-p2.first) == abs(p1.second - p2.second)) return true;
  return false;
}

inline decboard(int board[50][50], position &p1)
{
  for(int i = 1 ; i < n ; i ++){


    int x1 = p1.first - i;
    int x2 = p1.first + i;
    int y1 = p1.second - i;
    int y2 = p1.second + i;
    if(x1 >= 0 && y1 >= 0) board[x1][y1] --;
    if(x2 <  n && y1 >= 0) board[x2][y1] --;
    if(x1 >= 0 && y2 <  n) board[x1][y2] --;
    if(x2 <  n && y2 <  n) board[x2][y2] --;


  }
}

inline incboard(int board[50][50], position &p1)
{
  for(int i = 1 ; i < n ; i ++){


    int x1 = p1.first - i;
    int x2 = p1.first + i;
    int y1 = p1.second - i;
    int y2 = p1.second + i;
    if(x1 >= 0 && y1 >= 0) board[x1][y1] ++;
    if(x2 <  n && y1 >= 0) board[x2][y1] ++;
    if(x1 >= 0 && y2 <  n) board[x1][y2] ++;
    if(x2 <  n && y2 <  n) board[x2][y2] ++;


  }
}


int main(void)
{
  int board[50][50];
//  int n;
  cin >> n;

  int i;

  vector<position> poss;
  for(i = 0 ; i < n ; i ++){
    int x,y;
    cin >> x >> y;
    poss.push_back(pair<int,int>(x-1,y-1));
  }

  int ul = 0;
//  vector<vector<position> > results;

  for(int y = 0 ; y < n ; y ++){
    for(int x = 0 ; x < n ; x ++){
      board[x][y] = 0;
    }
  }

  for( int k = 0 ; k < n ; k ++){
//    if(k == first || k == second  || k == third) continue;
    for(int i = 1 ; i < n ; i ++){

//      board[poss[k].first][i] ++;
//      board[i][poss[k].second] ++;
//      if( i > 0){
        int x1 = poss[k].first - i;
        int x2 = poss[k].first + i;
        int y1 = poss[k].second - i;
        int y2 = poss[k].second + i;
        if(x1 >= 0 && y1 >= 0) board[x1][y1] ++;
        if(x2 <  n && y1 >= 0) board[x2][y1] ++;
        if(x1 >= 0 && y2 <  n) board[x1][y2] ++;
        if(x2 <  n && y2 <  n) board[x2][y2] ++;

//      }
    }
  }
        // board maked
  for(int first= 0 ; first< n - 2 ; first++){
    for(int second = first + 1 ; second < n - 1 ; second ++){
      for(int third = second + 1 ; third < n ; third ++){
        decboard(board, poss[first]);
        decboard(board, poss[second]);
        decboard(board, poss[third]);
        vector<position> toplace;
        vector<int> xs;
        xs.push_back(poss[first].first);
        xs.push_back(poss[second].first);
        xs.push_back(poss[third].first);
        vector<int> ys;
        ys.push_back(poss[first].second);
        ys.push_back(poss[second].second);
        ys.push_back(poss[third].second);

        for(i = 0; i< 3; i++){
          for(int j = 0; j < 3; j++){
            if(board[xs[i]][ys[j]] ==0) toplace.push_back(make_pair(xs[i], ys[j]));
          }
        }

        /*
        cout << "u " << toplace.size() << endl;
        for(i = 0 ; i < toplace.size() ; i ++){
          cout << toplace[i].first << "," << toplace[i].second << endl;
        }
          */
        
        for(i = 0 ; i < toplace.size()-2 ; i ++){
          for(int  t = i+1 ; t < toplace.size() - 1 ; t ++){
            if(isBakon(toplace[i],toplace[t]) == false)
              for(int j = t + 1 ; j < toplace.size() ; j++){
//                cout << "uhoho" << endl;
                if(isBakon(toplace[i],toplace[j]) == false && isBakon(toplace[t],toplace[j]) == false){
//                  cout << "uhohohoho" << endl;
                  vector<position> result;
                  result.push_back(toplace[i]);
                  result.push_back(toplace[t]);
                  result.push_back(toplace[j]);

                  if(find(result.begin(), result.end(), poss[first]) != result.end())
                    continue;
                  if(find(result.begin(), result.end(), poss[second]) != result.end())
                    continue;
                  if(find(result.begin(), result.end(), poss[third]) != result.end())
                    continue;

                  /*
                  for(int k = 0; k < n; k++){
                    if(k == first || k == second || k == third)
                      continue;
                    else
                      result.push_back(poss[k]);
                  }*/
                  ul ++;
                  /*
                  sort(result.begin(), result.end());

                  if(find(results.begin(), results.end(), result) == results.end())
                    results.push_back(result);
                    */
                }
              }
          }
        }
        incboard(board, poss[first]);
        incboard(board, poss[second]);
        incboard(board, poss[third]);
      }
    }
  }

  cout << ul << endl;
  
}