#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int n;
vector<array<int, 2>> p;
ll solve(int l, int r) {
if(l == r) return 0;
int m = (l+r)/2;
ll re = solve(l, m) + solve(m+1, r);
int L = l, R = m+1;
vector<int> s, s2;
while(L <= m || R <= r) {
if(L <= m && (R > r || p[L][1] < p[R][1])) {
while(!s.empty() && p[s.back()][0] < p[L][0]) s.pop_back();
s.push_back(L++);
} else {
while(!s2.empty() && p[s2.back()][0] > p[R][0]) s2.pop_back();
int l = 0, r = (int)s.size()-1;
while(l <= r && !s2.empty()) {
int m = (l+r)/2;
if(p[s[m]][1] < p[s2.back()][1]) l = m+1;
else r = m-1;
}
re += (int)s.size()-l;
s2.push_back(R++);
}
}
sort(p.begin()+l, p.begin()+r+1, [&](auto &a, auto &b) { return a[1] < b[1]; });
return re;
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n; p.resize(n);
for(auto &[x, y] : p) cin >> x >> y;
vector<int> Y;
for(auto [x, y] : p) Y.push_back(y);
sort(Y.begin(), Y.end()), Y.erase(unique(Y.begin(), Y.end()), Y.end());
for(auto &[x, y] : p) y = lower_bound(Y.begin(), Y.end(), y) - Y.begin() + 1;
sort(p.begin(), p.end());
cout << solve(0, n-1);
}
