#include <bits/stdc++.h>
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a), i##_len = (b); i < i##_len; ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define _repr(i, n) repri(i, n, 0)
/* loop in [n,m] step -1 */
#define repri(i, a, b) for(int i = int(a), i##_len = (b); i >= i##_len; --i)
/* loop in [n,0] step -1 or [n,m] step -1 */
#define repr(...) _overload3(__VA_ARGS__, repri, _repr, )(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << ": " << (x) << '\n'
typedef long long lint;
#define int lint
const int INF = (int)(1 << 30) - 1;
int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
const lint LINF = (lint)(1LL << 62) - 1;
typedef vector<int> vint;
typedef pair<int, int> pint;

struct IoSetup {
    IoSetup() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(10);
        cerr << fixed << setprecision(10);
    }
} iosetup;

#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define SZ(x) ((int)(x).size())

/* range macro. usage: for(int i:range(n)) */
class range {
   private:
    struct I {
        int x;
        int operator*() { return x; }
        bool operator!=(I &lhs) { return x < lhs.x; }
        void operator++() { ++x; }
    };
    I i, n;

   public:
    range(int n) : i({0}), n({n}) {}
    range(int i, int n) : i({i}), n({n}) {}
    I &begin() { return i; }
    I &end() { return n; }
};

/* keep a max,min */
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(a > b) {
        a = b;
        return 1;
    }
    return 0;
}

/* input,output operator for pair and vector */
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> p) {
    os << "(" << p.first << "," << p.second << ")";
    return os;
}

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
    os << p.first << " " << p.second;
    return os;
}

template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
    is >> p.first >> p.second;
    return is;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    for(int i = 0; i < (int)v.size(); i++) {
        os << v[i] << (i + 1 != v.size() ? ", " : "");
    }
    os << "]";
    return os;
}

template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
    for(T &in : v) is >> in;
    return is;
}

/* initialize vector. usage: auto v = male_v<int>(N,0); */
template <typename T>
vector<T> make_v(size_t a) {
    return vector<T>(a);
}

template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

/* fill vector. usage: fill_v(v,0); */
template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) {
    t = v;
}

template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) {
    for(auto &e : t) fill_v(e, v);
}

/* sum */
template <typename T>
T sum(vector<T> &v) {
    T ret;
    for(T x : v) {
        ret += x;
    }
    return ret;
}
template <typename T>
auto sum(const T &a) {
    return a;
}
template <typename T, typename... A>
auto sum(const T &first, const A &... rest) {
    return sum(first) + sum(rest...);
}

/* print */
void print() { cout << endl; }
template <typename T, typename... A>
void print(const T &first, const A &... rest) {
    cout << first << " ";
    print(rest...);
}
template <typename... A>
void print(const A &... rest) {
    print(rest...);
}

// BEGIN CUT HERE
struct UnionFind {
    int n, num;
    vector<int> r, p;
    UnionFind() {}
    UnionFind(int sz) : n(sz), num(sz), r(sz, 1), p(sz, 0) {
        iota(p.begin(), p.end(), 0);
    }
    int root(int x) { return (x == p[x] ? x : p[x] = root(p[x])); }
    bool same(int x, int y) { return root(x) == root(y); }
    void unite(int x, int y) {
        x = root(x);
        y = root(y);
        if(x == y) return;
        if(r[x] < r[y]) swap(x, y);
        r[x] += r[y];
        p[y] = x;
        num--;
    }
    int size(int x) { return r[root(x)]; }
    int count() const { return num; }
};
// END CUT HERE

signed main() {
    /* input part */
    int MAX = 110000;
    int N;
    cin >> N;
    UnionFind uf(2 * MAX);
    int x, y;
    for(int i : range(N)) {
        cin >> x >> y;
        uf.unite(x, y + MAX);
    }
    map<int, int> mx, my;
    for(auto x : range(MAX)) {
        mx[uf.root(x)]++;
    }
    for(auto y : range(MAX, 2 * MAX)) {
        my[uf.root(y)]++;
    }
    int ret = 0;
    for(int i : range(MAX * 2)) {
        ret += mx[i] * my[i];
    }
    print(ret - N);
}


Measured memory_bytes: 31232