#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#pragma GCC target("avx2")
using namespace std;
using ll = long long;
const int MAXN = 2e5 + 10;
vector<int> x, y;
template<typename T>
struct seg {
int n; // 크기 (1-based로 쓰려면 1크게 넣어야 함)
T id; // 항등원
vector<T> t;
T (*merge)(T, T);
seg(int N, T ID, T (*_merge)(T, T)) : n(N), id(ID), merge(_merge) { t.resize(N << 1, id); }
void update(int p, T val) {
for (t[p += n] = val; p > 1; p >>= 1) { // 기존 거랑 비교해서 바꿔야 하면 t[p+=n] = '그 값'으로 수정 필요.
if (p & 1) t[p >> 1] = merge(t[p ^ 1], t[p]);
else t[p >> 1] = merge(t[p], t[p ^ 1]);
}
}
T query(int l, int r) { // query on interval [l, r)
T lret = id, rret = id;
for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
if (l & 1) lret = merge(lret, t[l++]);
if (r & 1) rret = merge(t[--r], rret);
}
return merge(lret, rret);
}
};
int n;
pair<int, int> p[MAXN];
ll ans;
void dnc(int l, int r) {
if (l >= r) return;
if (l + 1 == r) {
ans += (p[l].second < p[r].second);
return;
}
int m = l + r >> 1;
dnc(l, m), dnc(m + 1, r);
vector<array<int, 3>> v;
set<int> s{n + 1};
for (int i = m; i >= l; i--) {
auto [x, y] = p[i];
auto h = *s.lower_bound(y);
v.push_back({y, h, 0}), s.insert(y);
}
s = set<int>{0};
for (int i = m + 1; i <= r; i++) {
auto [x, y] = p[i];
auto h = *prev(s.lower_bound(y));
v.push_back({h, y, 1}), s.insert(y);
}
sort(v.begin(), v.end());
seg<int> sg(y.size() + 10, 0, [](int x, int y) { return x + y; });
for (auto& [low, high, op]: v) {
if (op) sg.update(high, 1);
else ans += sg.query(low, high);
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> p[i].first >> p[i].second;
x.push_back(p[i].first), y.push_back(p[i].second);
}
sort(p + 1, p + n + 1);
sort(x.begin(), x.end());
x.erase(unique(x.begin(), x.end()), x.end());
sort(y.begin(), y.end());
y.erase(unique(y.begin(), y.end()), y.end());
for (int i = 1; i <= n; i++) {
p[i].first = lower_bound(x.begin(), x.end(), p[i].first) - x.begin() + 1;
p[i].second = lower_bound(y.begin(), y.end(), p[i].second) - y.begin() + 1;
}
dnc(1, n);
cout << ans;
return 0;
}
