#include <bits/stdc++.h>

using Pos = std::pair<int, int>;
int main ()
{
    int N;
    std::cin >> N;
    int x, y;
    std::vector<Pos> positions, same_y;
    size_t cnt = 0;
    for (int i = 0; i < N; ++i)
    {
        std::cin >> x >> y;
        positions.push_back({x,y});
        same_y.push_back({x,y});
    }
    std::sort(positions.begin(), positions.end(), [] (const Pos & a, const Pos & b){
        if (a.first == b.first) return a.second < b.second;
        return a.first < b.first; 
    });

    std::sort(same_y.begin(), same_y.end(), [] (const Pos & a, const Pos & b){
        if (a.second == b.second) return a.first < b.first;
        return a.second < b.second; 
    });

    for (size_t i = 0; i + 1 < positions.size(); ++i)
    {
        if (positions[i].first == positions[i+1].first)
            cnt++;
        if (same_y[i].second == same_y[i+1].second)
            cnt++;
    }
   
    std::cout << positions.size() - cnt  - 1 << std::endl;
    return 0;
}