#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T> bool maximize(T &a, const T &b){ return (a < b ? a = b, 1 : 0); }
template<class T> bool minimize(T &a, const T &b){ return (a > b ? a = b, 1 : 0); }
#define fi first
#define se second
#define pb push_back
#define ii pair<int, int>
#define all(x) x.begin(), x.end()
#define TASK "nonsense"
/// end of template ///
mt19937 gen(std::chrono::steady_clock::now().time_since_epoch().count());
int rdint(int l, int r)
{
return uniform_int_distribution<int>(l,r)(gen);
}
const int N = 2e5 + 10;
struct Point
{
int x,y;
Point() {}
void input()
{
cin>>x>>y;
}
bool operator < (const Point &S) const
{
return x<S.x;
}
} point[N];
int n,a[N],track[N],bit[N];
ii p[N];
vector<int> nen;
ll dnc(int l, int r)
{
if(l==r) return 0;
int mid((l+r)>>1);
int ptr=0;
for(int i=l;i<=r;++i) p[++ptr]={a[i],i};
sort(p+1,p+1+ptr);
int num=0;
ll ans=0;
for(int tri=1;tri<=ptr;++tri)
{
int pos=p[tri].se;
if(pos<=mid)
{
while(num>0 && track[num]<pos) --num;
track[++num]=pos;
}
else
{
int mx=0;
int x=pos;
while(x>=mid+1)
{
maximize(mx,bit[x]);
x-=x&-x;
}
int lo=1,hi=num,mid,cm=num+1;
while(lo<=hi)
{
mid=(lo+hi)>>1;
if(a[track[mid]]>mx) cm=mid,hi=mid-1;
else lo=mid+1;
}
ans+=num-cm+1;
x=pos;
while(x<=r)
{
maximize(bit[x],a[pos]);
x+=x&-x;
}
}
}
for(int i=mid+1;i<=r;++i) bit[i]=0;
ans+=dnc(l,mid);
ans+=dnc(mid+1,r);
return ans;
}
void solve()
{
cin>>n;
for(int i=1;i<=n;++i) point[i].input();
sort(point+1,point+1+n);
for(int i=1;i<=n;++i) a[i]=point[i].y,nen.pb(a[i]);
sort(all(nen));
nen.erase(unique(all(nen)),nen.end());
for(int i=1;i<=n;++i) a[i]=lower_bound(all(nen),a[i])-nen.begin()+1;
cout<<dnc(1,n);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
// freopen(TASK".inp","r",stdin);
// freopen(TASK".out","w",stdout);
int testcase=1;
// cin>>testcase;
while (testcase--)
solve();
return 0;
}
