#include <iostream>
#ifdef MBP
#include "stdc++.h"
#else
#include <bits/stdc++.h>
#endif

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define REP(i, n) for (long long int i = 0, i##_len = (n); i < i##_len; ++i)
#define REP_R(i, n) for (long long int i = (n - 1); i >= 0; --i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((long long int)(x).size())
#define BIT(n) (1LL << (n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());

#define INF INT_MAX
#define INFLL LLONG_MAX
#define PB push_back
#define MOD 1000000007LL
#define LSB(x) __builtin_ctzll(x)
#define MSB(x) 64LL - __builtin_clzll(x) - 1LL
#define MSBINT(x) 32LL - __builtin_clz(x)
#define BITCNT(x) __builtin_popcountll(x)

using namespace std;
using uif = uint_fast64_t;
using ll = long long int;
using vec = vector<ll>;
using mat = vector<vector<ll>>;
using pa = pair<ll, ll>;
using tTree = __gnu_pbds::tree<ll, __gnu_pbds::null_type, less<ll>, __gnu_pbds::rb_tree_tag, __gnu_pbds::tree_order_statistics_node_update>;

template <class T>
using PQ = priority_queue<T>;
template <class T>
using PQG = priority_queue<T, vector<T>, greater<T>>;

const ll dx[4] = {1, 0, -1, 0};
const ll dy[4] = {0, 1, 0, -1};
const ll dx8[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll dy8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

template <class T>
bool chmax(T &, const T &);
template <class T>
bool chmin(T &, const T &);
ll gcd(ll, ll);
ll qp(ll a, ll b);
ll qp(ll a, ll b, ll mo);

ll mod_pow(ll, ll);
ll mod_add(ll, ll);
ll mod_mul(ll, ll);
ll mod_div(ll, ll);
void make_fact(ll);
void make_invfact(ll);
void init_fact();

ll combination(ll, ll);

#define FACSIZE 200002LL

ll invfac[FACSIZE];
ll fac[FACSIZE];

vector<ll> dp;
void init(ll);
ll root(ll);
void unite(ll, ll);
bool same(ll, ll);

struct edge
{
  ll to, cost, id;
};

class Graph
{
public:
  ll N;
  vector<vector<edge>> G;

  Graph(ll N) : N(N)
  {
    G = vector<vector<edge>>(N, vector<edge>(0));
  }

  void add_Directed_edge(ll from, ll to, ll cost = 1, ll id = 0)
  {
    G[from].push_back(edge({to, cost, id}));
  }

  void add_Undirected_edge(ll v1, ll v2, ll cost = 1, ll id = 0)
  {
    add_Directed_edge(v1, v2, cost, id);
    add_Directed_edge(v2, v1, cost, id);
  }

  mat waeshall_floyd()
  {
    mat d(N, vec(N, INF));
    REP(i, N)
    d[i][i] = 0;
    REP(i, N)
    for (edge e : G[i])
    {
      d[i][e.to] = min(d[i][e.to], e.cost);
    }
    REP(k, N)
    REP(i, N)
    REP(j, N)
    d[i][j] = min(d[i][j], d[i][k] + d[k][j]);

    return d;
  }
};

int main(void)
{
  ll n;
  cin >> n;
  vec X(n);
  vec Y(n);
  REP(i, n)
  cin >> X[i] >> Y[i];

  unordered_map<ll, ll> umX;
  unordered_map<ll, ll> umY;
  ll cntX = 0;
  ll cntY = 0;
  REP(i, n)
  {
    if (umX.find(X[i]) == end(umX))
    {

      umX[X[i]] = cntX;
      cntX++;
    }
    if (umY.find(Y[i]) == end(umY))
    {
      umY[Y[i]] = cntY;
      cntY++;
    }
  }
  /*
  for (auto p : umX)
  {
    cout << p.first << "," << p.second << endl;
  }
  cout << endl;
  for (auto p : umY)
  {
    cout << p.first << "," << p.second << endl;
  }
  cout << endl;
  //*/
  //cout << cntX << "-" << cntY << endl;

  init(cntX + cntY);
  REP(i, n)
  {
    //cout << "unite:" << umX[X[i]] << "," << umY[Y[i]] + cntX << endl;

    unite(umX[X[i]], umY[Y[i]] + cntX);
  }
  unordered_map<ll, ll> umE;
  REP(i, n)
  {
    umE[root(umX[X[i]])]++;
  }
  unordered_map<ll, ll> RX;
  unordered_map<ll, ll> RY;
  for (auto px : umX)
  {
    auto r = root(px.second);
    RX[r]++;
  }
  for (auto py : umY)
  {
    auto r = root(py.second + cntX);
    RY[r]++;
  }
  ll ans = 0;
  for (auto p : RX)
  {
    if (RY.find(p.first) != end(RY))
    {
      //cout << p.first << endl;
      //cout << p.second << "," << RY[p.first] << "," << umE[p.first] << endl;
      ans += p.second * RY[p.first] - umE[p.first];
    }
  }

  cout << ans << endl;
  /*
  Graph G(umX.size() + umY.size());

  REP(i, n)
  {

    G.add_Undirected_edge(umX[X[i]], umY[Y[i]] + umX.size(), 1, i);
  }
  //*/

  return 0;
}

template <class T>
bool chmax(T &a, const T &b)
{
  if (a < b)
  {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b)
{
  if (b < a)
  {
    a = b;
    return 1;
  }
  return 0;
}

ll qp(ll a, ll b)
{
  ll ans = 1LL;
  do
  {
    if (b & 1LL)
      ans = 1LL * mod_mul(ans, a) % MOD;
    a = 1LL * mod_mul(a, a) % MOD;
  } while (b >>= 1LL);
  return ans;
}
ll qp(ll a, ll b, ll mo)
{
  ll ans = 1LL;
  do
  {
    if (b & 1LL)
      ans = 1LL * (ans % mo) * (a % mo);
    a = 1LL * (a % mo) * (a % mo);
  } while (b >>= 1LL);
  return ans;
}
ll gcd(ll a, ll b)
{
  return b ? gcd(b, a % b) : a;
}
ll mod_pow(ll x, ll r)
{
  if (r == 0)
    return 1;
  else if (r == 1)
    return x % MOD;
  else if (r % 2 == 0)
  {
    ll t = mod_pow(x, r / 2) % MOD;
    return t * t % MOD;
  }
  else
  {
    ll t = mod_pow(x, r / 2) % MOD;
    ll k = t * t % MOD;
    return k * x % MOD;
  }
}
ll mod_add(ll a, ll b)
{
  return (a + b) % MOD;
}

ll mod_mul(ll a, ll b)
{
  return (a * b) % MOD;
}

ll mod_div(ll a, ll b)
{
  return mod_mul(a, mod_pow(b, MOD - 2));
}

void make_fact(ll n)
{
  fac[0] = 1;
  REP(i, n)
  {
    fac[i + 1] = mod_mul(fac[i], i + 1);
  }
}

void make_invfact(ll n)
{
  invfac[n] = mod_pow(fac[n], MOD - 2);
  REP_R(i, n)
  {
    invfac[i] = mod_mul(invfac[i + 1], i + 1);
  }
}

void init_fact()
{
  make_fact(FACSIZE - 1);
  make_invfact(FACSIZE - 1);
}

ll combination(ll n, ll c)
{

  return mod_mul(fac[n], mod_mul(invfac[c], invfac[n - c]));
}
///////////////fact
/*
  init_fact();
  cout << fac[5] << endl;
  cout << invfac[5] << endl;
  cout << combination(8, 4) << endl;
  cout << combination(31, 8) << endl;
  //*/
///////////////////

void init(ll n)
{
  dp.resize(n);
  REP(i, n)
  dp[i] = i;
}
ll root(ll x)
{
  if (dp[x] == x)
    return x;
  else
    return dp[x] = root(dp[x]);
}
void unite(ll x, ll y)
{
  auto rx = root(x);
  auto ry = root(y);
  dp[ry] = dp[rx];
  root(y);
}
bool same(ll x, ll y)
{
  return root(x) == root(y);
}

Measured memory_bytes: 6680