#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int miy[202020];
int main() {
cin.tie(nullptr)->sync_with_stdio(0);
int N;
cin >> N;
vector<pair<int,int>> p(N);
for (auto&[x,y] : p) cin >> x >> y;
sort(p.begin(),p.end());
function<ll(int,int)> f = [&](int l, int r) {
if (l >= r) return 0LL;
int m = l+r >> 1;
ll ret = f(l,m) + f(m+1,r);
vector<array<int,3>> L, now;
vector<int> stk, idx;
for (int i = l; i <= m; i++) L.push_back({p[i].first, p[i].second, i});
for (int i = l; i <= r; i++) now.push_back({p[i].first, p[i].second, i});
sort(L.begin(),L.end(),greater<>());
set<int> s;
s.insert((int)1e9+1);
for (auto[x,y,i] : L){
miy[i] = *s.lower_bound(y);
s.insert(y);
}
sort(now.begin(), now.end(), [](array<int,3> a, array<int,3> b){ return a[1] > b[1]; });
for (auto[x,y,i] : now) {
if (i <= m)
ret += lower_bound(stk.begin(),stk.end(),y,greater<>()) - upper_bound(stk.begin(),stk.end(),miy[i],greater<>());
else {
while (stk.size() and p[idx.back()].first > x) {
stk.pop_back();
idx.pop_back();
}
stk.push_back(y);
idx.push_back(i);
}
}
return ret;
};
cout << f(0, N-1);
}
