#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
int n;
pii p[200010];
vector<pii> tree[4*200010];
void update(int h,int tl,int tr,int x,int y) {
if(tr<y||y<tl)return;
while(!tree[h].empty()&&tree[h].back().se<y)
tree[h].pop_back();
tree[h].push_back({x,y});
if(tl==tr)return;
int mid=(tl+tr)/2;
update(h*2,tl,mid,x,y);
update(h*2+1,mid+1,tr,x,y);
}
pii query(int h,int tl,int tr,int l,int r,pii c) {
if(r<tl||tr<l) return c;
if(l<=tl&&tr<=r) {
if(tree[h].empty()) return c;
int i=lower_bound(all(tree[h]),make_pair(c.fi+1,-1))-tree[h].begin();
return {max(tree[h].back().fi,c.fi), c.se+sz(tree[h])-i};
}
int mid=(tl+tr)/2;
pii qr=query(h*2+1,mid+1,tr,l,r,c);
return query(h*2,tl,mid,l,r,qr);
}
int main() {
scanf("%d",&n);
int i;
vector<int> vx,vy;
for(i=1;i<=n;i++){
scanf("%d%d",&p[i].fi,&p[i].se);
vx.push_back(p[i].fi);
vy.push_back(p[i].se);
}
sort(all(vx));
vx.erase(unique(all(vx)),vx.end());
sort(all(vy));
vy.erase(unique(all(vy)),vy.end());
for(i=1;i<=n;i++) {
p[i].fi=lower_bound(all(vx),p[i].fi)-vx.begin();
p[i].se=lower_bound(all(vy),p[i].se)-vy.begin();
}
sort(p+1,p+n+1,[&](const pii& a,const pii& b) {
return a.fi==b.fi?a.se>b.se:a.fi<b.fi;
});
ll res=0;
for(i=1;i<=n;i++) {
pii r=query(1,0,sz(vy),0,p[i].se-1,make_pair(-1,0));
res+=r.se;
//printf("(%d,%d):%d\n",vx[p[i].fi],vy[p[i].se],r.se);
update(1,0,sz(vy),p[i].fi,p[i].se);
}
printf("%lld",res);
return 0;
}
