#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MN = 200010;
int N;
pii P[MN];
int A[MN];
vector<int> X, Y;
unordered_map<int, int> dx, dy;
void add(int x, int v, vector<pii> &stk) {
while(!stk.empty() && stk.back().first > v) stk.pop_back();
stk.push_back(pii(v, x));
}
struct BIT {
vector<vector<pii> > tree;
void init() {
tree = vector<vector<pii> >(4 * N);
}
void upd(int x, int v, int l, int r, int n) {
if(x < l || r < x) return;
add(v, x, tree[n]);
if(l == r) return;
int m = (l + r)>>1;
upd(x, v, l, m, 2*n);
upd(x, v, m + 1, r, 2*n + 1);
}
int quer(int a, int b, int &v, int l, int r, int n) {
if(b < l || r < a) return 0;
if(a <= l && r <= b) {
int s = 0, e = (int)tree[n].size() - 1, p = (int)tree[n].size();
while(s <= e) {
int m = (s + e)>>1;
if(tree[n][m].second < v) {
p = m;
e = m - 1;
}
else s = m + 1;
}
if(p != tree[n].size()) v = tree[n].back().second;
return (int)tree[n].size() - p;
}
int m = (l + r)>>1;
int L = quer(a, b, v, l, m, 2*n);
int R = quer(a, b, v, m + 1, r, 2*n + 1);
return L + R;
}
} bit;
int main() {
scanf("%d", &N);
for(int i = 0; i < N; i++) {
scanf("%d %d", &P[i].first, &P[i].second);
X.push_back(P[i].first);
Y.push_back(P[i].second);
}
sort(X.begin(), X.end());
sort(Y.begin(), Y.end());
X.resize(unique(X.begin(), X.end()) - X.begin());
Y.resize(unique(Y.begin(), Y.end()) - Y.begin());
for(int i = 0; i < N; i++) {
dx[X[i]] = i;
dy[Y[i]] = i;
}
for(int i = 0; i < N; i++) {
P[i].first = dx[P[i].first];
P[i].second = dy[P[i].second];
A[ P[i].first ] = P[i].second;
}
ll ans = 0;
bit.init();
for(int i = N - 1; i >= 0; i--) {
int t = N;
ans += bit.quer(A[i], N - 1, t, 0, N - 1, 1);
bit.upd(A[i], i, 0, N - 1, 1);
}
printf("%lld", ans);
}
