#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(s>p.second || 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(lit==rit) 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);
}
