#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <climits>
#include <cstring>
#include <cassert>


using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<n;++i)
#define FOR(i, a, b) for(int i=a;i<b;++i)
#define RREP(i, n) for(int i=n-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=b-1;i>=a;--i)

#define all(x) begin(x),end(x)
#define dump(x) cerr<<#x<<" = "<<(x)<<endl
#define debug(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

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

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

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

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


class UnionFind {
    vector<int> p;//p[i]はiの属する組織
    vector<int> sz;

public:
    vector<int> wall; //壁の上下左右どこにくっついているか
    UnionFind(int n) {
        p.resize(n);
        sz.resize(n);
        wall.resize(n);

        for (int i = 0; i < n; i++) {
            p[i] = i;
            sz[i] = 1;
        }
    }

/* xの属する集合を返す */
    int find(int x) {
        if (p[x] == x) return x;
        return p[x] = find(p[x]);
    }

/* yにxを統合する */
    void unite(int x, int y) {
        sz[find(y)] += sz[find(x)];
        sz[find(x)] = 0;
        wall[find(y)] |= wall[find(x)];
        p[find(x)] = p[find(y)];
    }

/* xとyが属する集合が同じかを判定する */
    bool same(int x, int y) {
        return find(x) == find(y);
    }

/* xに属する集合のサイズを求める */
    int size(int x) {
        return sz[find(x)];
    }
};


void solve() {
    ll N, W, H;
    cin >> N >> W >> H;
    UnionFind uf(N);
    struct slime {
        ll id, x, y;
    };
    vector<slime> sl(N);

    REP(i, N) {
        cin >> sl[i].x >> sl[i].y;
        sl[i].id = i;
        if (sl[i].x == 1) {
            uf.wall[i] |= 1;
        }

        if (sl[i].x == W) {
            uf.wall[i] |= 1 << 1;
        }

        if (sl[i].y == 1) {
            uf.wall[i] |= 1 << 2;
        }

        if (sl[i].y == H) {
            uf.wall[i] |= 1 << 3;
        }
    }

    sort(all(sl), [](auto l, auto r) {
        return l.x < r.x;
    });

    REP(i, N - 1) {
        if (sl[i].x == sl[i + 1].x) {
            if (!uf.same(sl[i].id, sl[i + 1].id)) {
                uf.unite(sl[i].id, sl[i + 1].id);
            }
        }
    }

    sort(all(sl), [](auto l, auto r) {
        return l.y < r.y;
    });

    REP(i, N - 1) {
        if (sl[i].y == sl[i + 1].y) {
            if (!uf.same(sl[i].id, sl[i + 1].id)) {
                uf.unite(sl[i].id, sl[i + 1].id);
            }
        }
    }


    ll ans = LINF;
    vector<ll> dec(4, 0);
    REP(i, N) {
        if (i == uf.find(i)) {
            REP(k, 4) {
                dec[k]++;
                if (uf.wall[uf.find(i)] >> k & 1) {
                    dec[k]--;
                }
            }
        }


    }
    REP(k, 4) {
        chmin(ans, N - 1 + dec[k]);
    }
    if (uf.size(0) == N) {
        chmin(ans, N - 1);
    }
    cout << ans << endl;


}


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
//    std::ifstream in("input.txt");
//    std::cin.rdbuf(in.rdbuf());

    solve();


    return 0;
}



Measured memory_bytes: 4056