#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector<pair<int, int>> bridges(n);
    for (int i = 0; i < n; ++i) {
        cin >> bridges[i].first >> bridges[i].second;
    }
    // Sap xep theo toa do ben trai (u)
    sort(bridges.begin(), bridges.end());

    long long ans = 0;
    // Su dung quy hoach dong O(n^2) de dem so nghich the
    // dp[i] la so luong phan tu lon hon v[i] o ben phai
    for (int i = 0; i < n; ++i) {
        for (int j = i + 1; j < n; ++j) {
            if (bridges[i].second > bridges[j].second) {
                ans++;
            }
        }
    }
    cout << ans << endl;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
using int64 = long long;

struct Fenwick {
    int n;
    vector<int64> bit;
    Fenwick(int n=0): n(n), bit(n+1,0) {}
    void add(int idx, int64 val){
        for(; idx<=n; idx += idx & -idx) bit[idx] += val;
    }
    int64 sum(int idx){
        int64 r = 0;
        for(; idx>0; idx -= idx & -idx) r += bit[idx];
        return r;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    if(!(cin >> N)) return 0;
    vector<pair<long long,long long>> a(N);
    for(int i=0;i<N;i++){
        long long u,v;
        cin >> u >> v;
        a[i] = {u,v};
    }

    // Sap xep theo u
    sort(a.begin(), a.end());

    // Coordinate compression for v
    vector<long long> vals;
    vals.reserve(N);
    for(auto &p: a) vals.push_back(p.second);
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());

    Fenwick bit(vals.size());
    int64 ans = 0;
    for(int i=0;i<N;i++){
        long long v = a[i].second;
        // Tim chi so trong mang da compress
        int idx = lower_bound(vals.begin(), vals.end(), v) - vals.begin() + 1;
        // Dem so luong phan tu da them vao ma co v > v hien tai
        // Tong so phan tu da them la i
        // So luong phan tu co v <= v hien tai la bit.sum(idx)
        // Vay so luong phan tu co v > v hien tai la i - bit.sum(idx)
        ans += i - bit.sum(idx);
        bit.add(idx, 1);
    }
    cout << ans << endl;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

int n;
vector<pair<int,int>> a;
vector<int> b;

long long c = 0;

// Ham dem so nghich the trong mang b
void f(vector<int>& v, int l, int r) {
    if (l >= r) return;
    int m = (l + r) / 2;
    f(v, l, m);
    f(v, m+1, r);
    vector<int> t;
    int i = l, j = m+1;
    while (i <= m && j <= r) {
        if (v[i] <= v[j]) t.push_back(v[i++]);
        else {
            t.push_back(v[j++]);
            // Neu v[i] > v[j] va i o ben trai (da sap xep), 
            // thi tat ca phan tu tu i den m deu lon hon v[j]
            c += m - i + 1;
        }
    }
    while (i <= m) t.push_back(v[i++]);
    while (j <= r) t.push_back(v[j++]);
    for (i = l; i <= r; i++) v[i] = t[i-l];
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    a.resize(n);
    for (int i = 0; i < n; i++) cin >> a[i].first >> a[i].second;
    // Sap xep theo u
    sort(a.begin(), a.end());
    b.resize(n);
    for (int i = 0; i < n; i++) b[i] = a[i].second;
    // Dem nghich the tren mang v
    f(b, 0, n-1);
    cout << c;
}