/*
* Author: Nonoze
* Created: Tuesday 06/01/2026
*/
#include <bits/stdc++.h>
using namespace std;
#ifndef DEBUG
#define dbg(...)
#endif
// #define cout cerr << "OUT: "
#define endl '\n'
#define endlfl '\n' << flush
#define quit(x) return (void)(cout << x << endl)
template<typename T> void read(T& x) { cin >> x; }
template<typename T1, typename T2> void read(pair<T1, T2>& p) { read(p.first), read(p.second); }
template<typename T> void read(vector<T>& v) { for (auto& x : v) read(x); }
template<typename T1, typename T2> void read(T1& x, T2& y) { read(x), read(y); }
template<typename T1, typename T2, typename T3> void read(T1& x, T2& y, T3& z) { read(x), read(y), read(z); }
template<typename T1, typename T2, typename T3, typename T4> void read(T1& x, T2& y, T3& z, T4& zz) { read(x), read(y), read(z), read(zz); }
template<typename T> void print(vector<T>& v) { for (auto& x : v) cout << x << ' '; cout << endl; }
#define sz(x) (int)(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define make_unique(v) sort(all(v)), v.erase(unique(all(v)), (v).end())
#define pb push_back
#define mp(a, b) make_pair(a, b)
#define fi first
#define se second
#define cmin(a, b) a = min(a, b)
#define cmax(a, b) a = max(a, b)
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define QYES quit("YES")
#define QNO quit("NO")
#define int long long
#define double long double
const int inf = numeric_limits<int>::max() / 4;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9+7, LOG=20;
void solve();
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
int tt=1;
// cin >> tt;
while(tt--) solve();
return 0;
}
int n, k, m;
vector<int> a, nb;
void solve() {
read(n);
a.resize(100000);
vector<int> beg(100000, 0), end(100000, 0);
for (int i=0; i<n; i++) {
int h, x; read(h, x); h--;
beg[h-x+1]++;
end[h]++;
}
int cur=0;
for (int i=0; i<100000; i++) {
cur+=beg[i];
a[i]=cur;
cur-=end[i];
}
dbg(a, nb);
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> pq; pq.push({a[0], 1});
for (int i=1; i<100000; i++) {
if (pq.top().fi==a[i]) {
auto p=pq.top(); pq.pop();
p.se++;
pq.push(p);
continue;
}
if (!a[i]) {
pq.push({0, 1});
continue;
}
int need=a[i];
while (need>pq.top().fi) {
auto p=pq.top(); pq.pop();
if (!pq.empty()) {
int obj=pq.top().fi;
int total = (obj - p.fi) * p.se;
if (need - total >= obj) {
need-=total;
p.fi=obj, p.se+=pq.top().se; pq.pop();
pq.push(p);
continue;
}
}
int sm=p.fi*p.se + need, newh=sm/(p.se+1), rem=sm%(p.se+1);
if (rem==0) {
pq.push({newh, p.se+1});
} else {
if (!pq.empty() && pq.top().fi==newh+1) {
auto q=pq.top(); pq.pop();
pq.push({newh+1, q.se + rem});
} else {
pq.push({newh+1, rem});
}
pq.push({newh, p.se+1 - rem});
}
need=0;
}
if (need>0) {
if (!pq.empty() && pq.top().fi==need) {
auto p=pq.top(); pq.pop();
p.se++;
pq.push(p);
} else {
pq.push({need, 1});
}
}
}
int ans=0;
while (!pq.empty()) {
dbg(pq);
auto p=pq.top(); pq.pop();
ans+=(p.fi * (p.fi-1)) / 2 * p.se;
}
quit(ans);
}
