#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define MAX 201010
#define MAXS 20
#define INF 1000000000000000001
#define bb ' '
#define ln '\n'
#define Ln '\n'
int Y[MAX];
ll ans;
void solve(int l, int r) {
if (l == r) return;
int m = l + r >> 1;
int i;
vector<pii> lv, rv;
for (i = l; i <= m; i++) lv.emplace_back(i, Y[i]);
sort(lv.begin(), lv.end(), [&](pii a, pii b) {return a.second < b.second; });
for (i = m + 1; i <= r; i++) rv.emplace_back(i, Y[i]);
sort(rv.begin(), rv.end(), [&](pii a, pii b) {return a.second < b.second; });
vector<pii> stl, str; // y, x
int ptr = 0;
for (auto& [x, y] : rv) {
while (ptr < lv.size() && lv[ptr].second < y) {
while (stl.size() && stl.back().second < lv[ptr].first) stl.pop_back();
stl.emplace_back(lv[ptr].second, lv[ptr].first);
ptr++;
}
while (str.size() && str.back().second > x) str.pop_back();
int py = -10;
if (str.size()) py = str.back().first;
str.emplace_back(y, x);
int ind = upper_bound(stl.begin(), stl.end(), pii(py, 0)) - stl.begin();
ans += (ll)(stl.size()) - ind;
}
solve(l, m);
solve(m + 1, r);
}
signed main() {
ios::sync_with_stdio(false), cin.tie(0);
int N;
cin >> N;
vector<pii> vpi;
int i, a, b;
for (i = 1; i <= N; i++) cin >> a >> b, vpi.emplace_back(a, b);
sort(vpi.begin(), vpi.end());
i = 0;
for (auto& [_, y] : vpi) Y[++i] = y;
solve(1, N);
cout << ans << ln;
}
