#include <bits/stdc++.h>
#define pii pair<int, int>
using namespace std;
int N;
long long ans;
pii P[202020];
struct Node{
vector<pii> V;
Node *lc, *rc;
Node(){
lc = rc = NULL;
}
};
void update(Node *now, int s, int e, pii p){
if (p.second < s || e < p.second) return;
if (s == e){
now->V.push_back(p);
return;
}
int mid = (s+e)/2;
if (now->lc == NULL) now->lc = new Node;
update(now->lc, s, mid, p);
if (now->rc == NULL) now->rc = new Node;
update(now->rc, mid+1, e, p);
while (!now->V.empty() && now->V.back().second > p.second) now->V.pop_back();
now->V.push_back(p);
}
int query(Node *now, int s, int e, pii p, int xlim){
if (e <= p.second) return xlim;
if (s > p.second){
auto lit = lower_bound(now->V.rbegin(), now->V.rend(), p);
auto rit = lower_bound(now->V.rbegin(), now->V.rend(), pii(xlim, 0));
if (rit - lit == 0) return xlim;
ans += (rit - lit);
return lit->first;
}
int mid = (s+e)/2;
if (now->lc != NULL) xlim = query(now->lc, s, mid, p, xlim);
if (now->rc != NULL) xlim = query(now->rc, mid+1, e, p, xlim);
return xlim;
}
int main(){
scanf("%d", &N);
for (int i=1; i<=N; i++) scanf("%d %d", &P[i].first, &P[i].second);
sort(P+1, P+N+1, [&](pii A, pii B){
return A.second < B.second;
});
for (int i=1; i<=N; i++) P[i].second = i;
sort(P+1, P+N+1);
for (int i=1; i<=N; i++) P[i].first = i;
Node *Tree = new Node;
for (int i=N; i>0; i--){
update(Tree, 1, N, P[i]);
query(Tree, 1, N, P[i], N+1);
}
printf("%lld", ans);
return 0;
}
