/**
 * Sergey Kopeliovich (burunduk30@gmail.com)
 */

#include <bits/stdc++.h>

using namespace std;

#define forn(i, n) for (int i = 0; i < (int)(n); i++)
#define all(p) p.begin(), p.end()

int main() {
    int n;
    cin >> n;
    vector<pair<int, int>> p(n);
    forn(i, n)
        cin >> p[i].first >> p[i].second;
    sort(all(p));

    vector<int> t[2 * n]; // [n,2n)
    forn(i, n)
        t[i + n] = {p[i].second};
    for (int i = n - 1; i > 0; i--) {
        t[i].resize(t[i * 2].size() + t[i * 2 + 1].size());
        merge(all(t[2 * i]), all(t[2 * i + 1]), t[i].begin());
    }

    auto inner_get = [&](int i, int y1, int y2) {
        return upper_bound(all(t[i]), y2) - lower_bound(all(t[i]), y1);
    };
    auto get = [&](int x1, int x2, int y1, int y2) {
        int l = lower_bound(all(p), make_pair(x1, y1)) - p.begin();
        int r = upper_bound(all(p), make_pair(x2, y2)) - p.begin() - 1;

        int sum = 0;
        for (l += n, r += n; l <= r; l /= 2, r /= 2) {
            if (l % 2 == 1) sum += inner_get(l++, y1, y2);
            if (r % 2 == 0) sum += inner_get(r--, y1, y2);
        }
        return sum;
    };
}