#include <bits/stdc++.h>
using namespace std;

using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using ll = long long int;
using vll = vector<ll>; using vvll = vector<vll>; using vvvll = vector<vvll>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using cdouble = complex<double>;

const double eps = 1e-7;
#define Loop(i, n) for(int i = 0; i < int(n); i++)
#define Loopll(i, n) for(ll i = 0; i < ll(n); i++)
#define Loop1(i, n) for(int i = 1; i <= int(n); i++)
#define Loopll1(i, n) for(ll i = 1; i <= ll(n); i++)
#define Loopr(i, n) for(int i = int(n) - 1; i >= 0; i--)
#define Looprll(i, n) for(ll i = ll(n) - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = int(n); i >= 1; i--)
#define Looprll1(i, n) for(ll i = ll(n); i >= 1; i--)
#define Foreach(buf, container) for(auto buf : container)
#define Loopdiag(i, j, h, w, sum) for(int i = ((sum) >= (h) ? (h) - 1 : (sum)), j = (sum) - i; i >= 0 && j < (w); i--, j++)
#define Loopdiagr(i, j, h, w, sum) for(int j = ((sum) >= (w) ? (w) - 1 : (sum)), i = (sum) - j; j >= 0 && i < (h); j--, i++)
#define Loopdiagsym(i, j, h, w, gap) for (int i = ((gap) >= 0 ? (gap) : 0), j = i - (gap); i < (h) && j < (w); i++, j++)
#define Loopdiagsymr(i, j, h, w, gap) for (int i = ((gap) > (h) - (w) - 1 ? (h) - 1 : (w) - 1 + (gap)), j = i - (gap); i >= 0 && j >= 0; i--, j--)
#define Loopitr(itr, container) for(auto itr = container.begin(); itr != container.end(); itr++)
#define printv(vector) Loop(ex_i, vector.size()) { cout << vector[ex_i] << " "; } cout << endl;
#define printmx(matrix) Loop(ex_i, matrix.size()) { Loop(ex_j, matrix[ex_i].size()) { cout << matrix[ex_i][ex_j] << " "; } cout << endl; }
#define quickio() ios::sync_with_stdio(false); cin.tie(0);
#define bitmanip(m,val) static_cast<bitset<(int)m>>(val)
#define Comp(type_t) bool operator<(const type_t &another) const
#define fst first
#define snd second
#define INF INFINITY
bool feq(double x, double y) { return abs(x - y) <= eps; }
bool inrange(ll x, ll t) { return x >= 0 && x < t; }
bool inrange(vll xs, ll t) { Foreach(x, xs) if (!(x >= 0 && x < t)) return false; return true; }
int ceillog2(ll x) { int ret = 0;	x--; while (x > 0) { ret++; x >>= 1; } return ret; }
ll rndf(double x) { return (ll)(x + (x >= 0 ? 0.5 : -0.5)); }
ll floorsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (m * m <= x ? 0 : -1); }
ll ceilsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (x <= m * m ? 0 : 1); }
ll rnddiv(ll a, ll b) { return (a / b + (a % b * 2 >= b ? 1 : 0)); }
ll ceildiv(ll a, ll b) { return (a / b + (a % b == 0 ? 0 : 1)); }
ll gcd(ll m, ll n) { if (n == 0) return m; else return gcd(n, m % n); }
ll lcm(ll m, ll n) { return m * n / gcd(m, n); }

/*******************************************************/

class Union_Find {
private:
	vi p, r, c; // parent, rank, the number of connected components
public:
	Union_Find(int N) {
		p.resize(N);
		r.resize(N);
		c.resize(N);
		Loop(i, N) {
			p[i] = i;
			r[i] = 0;
			c[i] = 1;
		}
	}
	int find(int x) {
		if (p[x] == x) return x;
		else return p[x] = find(p[x]);
	}
	void unite(int x, int y) {
		x = find(x);
		y = find(y);
		if (x == y) return;
		if (r[x] == r[y]) r[x]++;
		if (r[x] < r[y]) {
			p[x] = y;
			c[y] += c[x];
		}
		else {
			p[y] = x;
			c[x] += c[y];
		}
	}
	bool is_same(int x, int y) {
		return find(x) == find(y);
	}
	int get_cnt(int x) {
		return c[find(x)];
	}
};

int main() {
	quickio();
	int n; cin >> n;
	vector<P> v(n);
	vvi x(100003), y(100003);
	Loop(i, n) {
		cin >> v[i].fst >> v[i].snd;
		x[v[i].fst].push_back(i);
		y[v[i].snd].push_back(i);
	}
	Union_Find *uf = new Union_Find(n);
	Loop(i, x.size()) {
		Loop(j, x[i].size() - 1) {
			uf->unite(x[i][j], x[i][j + 1]);
		}
	}
	Loop(i, y.size()) {
		Loop(j, y[i].size() - 1) {
			uf->unite(y[i][j], y[i][j + 1]);
		}
	}
	map<int, vi> mp;
	Loop(i, n) {
		mp[uf->find(i)].push_back(i);
	}
	ll cnt = 0;
	Loopitr(itr, mp) {
		set<int> xs, ys;
		Foreach(i, itr->snd) {
			xs.insert(v[i].fst);
			ys.insert(v[i].snd);
		}
		if (xs.size() > 1 && ys.size() > 1) {
			cnt += ll(xs.size()) * ys.size();
		}
		else {
			cnt += xs.size() + ys.size() - 1;
		}
	}
	cout << cnt - n << endl;
}

Measured memory_bytes: 15224