#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
typedef long long ll;
const int B = 1<<18;
ll ans, n, seg[B * 2];
void upd(int ix, int v) {
ix += B;
while (ix) {
seg[ix] += v;
ix >>= 1;
}
}
ll sum(int l, int r) {
ll ret = 0;
l += B; r += B;
while (l <= r) {
if (l & 1) ret += seg[l++];
if (!(r & 1)) ret += seg[r--];
l >>= 1; r >>= 1;
}
return ret;
}
void comp(vector<int>& v) {
vector<int> t;
for (int & x: v) t.emplace_back(x);
sort(all(t));
for (int i = 0; i < v.size(); i++) v[i] = lower_bound(all(t), v[i]) - t.begin();
}
void dnc(int l, int r, vector<pair<int,int>> & v) {
// cout << l << ' ' << r << ' ' << (l + r) / 2 << ' ' << ans << endl;
if (l == r) return;
int m = (l + r) / 2;
stack<int> s1, s2;
auto s1pop = [&] {
upd(v[s1.top()].first, -1); s1.pop();
};
vector<pair<int, int>> v1, v2;
for (int i = 0; i < v.size(); i++) {
auto&[y, x] = v[i];
if (x <= m) {
v1.emplace_back(v[i]);
while (s1.size() && v[s1.top()].second < x) s1pop();
s1.emplace(i); upd(y, 1);
}
else {
v2.emplace_back(v[i]);
while (s2.size() && v[s2.top()].second > x) s2.pop();
ans += sum((s2.empty() ? 0 : v[s2.top()].first + 1), y - 1);
s2.emplace(i);
}
}
// cout << "L : ";
// for (auto&[y, x] : v1) cout << x << ' ';
// cout << endl;
// cout << "R : ";
// for (auto&[y, x] : v2) cout << x << ' ';
// cout << endl;
while (s1.size()) s1pop();
dnc(l, m, v1); dnc(m + 1, r, v2);
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
vector<int> X(n),Y(n);
for (int i = 0; i < n; i++) cin >> X[i] >> Y[i];
comp(X);comp(Y);
vector<pair<int, int>> v(n);
for (int i = 0; i < n; i++) v[i] = {Y[i], X[i]};
sort(all(v));
dnc(0, n - 1, v);
cout << ans;
return 0;
}
