#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 2e5;
struct Point
{
int x, y;
Point() {}
Point(int x, int y) : x(x), y(y) {}
bool operator < (const Point& p)
{
return x<p.x;
}
};
int n, ans;
Point arr[MAXN+10];
vector<int> xpos, ypos;
int xcoord[MAXN+10];
vector<vector<Point>> tree;
void update(int node, int tl, int tr, int x, int y)
{
if(tl==tr) { tree[node]=vector<Point>(1, Point(x, y)); return; }
int mid=tl+tr>>1;
if(y<=mid) update(node*2, tl, mid, x, y);
else update(node*2+1, mid+1, tr, x, y);
while(!tree[node].empty() && tree[node].back().y<y) tree[node].pop_back();
tree[node].push_back({x, y});
}
int last=-1, ret=0;
void query(int node, int tl, int tr, int l, int r)
{
if(r<tl || tr<l) return;
if(l<=tl && tr<=r)
{
if(tree[node].empty()) return;
ret+=tree[node].end()-lower_bound(tree[node].begin(), tree[node].end(), Point(last, 0));
last=max(last, tree[node].back().x);
return;
}
int mid=tl+tr>>1;
query(node*2+1, mid+1, tr, l, r);
query(node*2, tl, mid, l, r);
}
void see(int node, int tl, int tr)
{
printf("%d %d : ", tl, tr);
for(Point i : tree[node]) printf("(%d %d) ", i.x, i.y);
printf("\n");
if(tl==tr) return;
int mid=tl+tr>>1;
see(node*2, tl, mid);
see(node*2+1, mid+1, tr);
}
int main()
{
int i, j;
scanf("%d", &n);
for(i=0; i<n; i++)
{
scanf("%d%d", &arr[i].x, &arr[i].y);
xpos.push_back(arr[i].x);
ypos.push_back(arr[i].y);
}
sort(xpos.begin(), xpos.end());
sort(ypos.begin(), ypos.end());
for(i=0; i<n; i++)
{
arr[i].x=lower_bound(xpos.begin(), xpos.end(), arr[i].x)-xpos.begin()+1;
arr[i].y=lower_bound(ypos.begin(), ypos.end(), arr[i].y)-ypos.begin()+1;
}
sort(arr, arr+n, [&](const Point& p, const Point& q)
{
return p.x<q.x;
});
tree.resize(n*4+10);
for(i=0; i<n; i++)
{
last=-1, ret=0;
query(1, 1, n, 1, arr[i].y);
ans+=ret;
//printf("%d\n", ret);
update(1, 1, n, arr[i].x, arr[i].y);
//see(1, 1, n);
}
printf("%d", ans);
}
