#include <bits/stdc++.h>
using namespace std;
#define f1r(i, a, b) for (int i = a; i < b; i++)
#define f0r(i, a) f1r(i, 0, a)
#define eb emplace_back
#define pb push_back
#define f first
#define s second
#define sz(x) (int) (x).size()
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
int main() {
cin.tie(0)->sync_with_stdio(0);
int n; cin >> n;
vl diff(n+1);
f1r(i, 1, n+1) {
int a, b; cin >> a >> b;
diff[i] = a-b + diff[i-1];
}
ll lst = 0;
multiset<ll> pq;
f1r(i, 1, n) {
if (diff[i] < 0) {
lst -= diff[i];
diff[i] = 0;
}
if (diff[i] > diff[n]) {
lst += diff[i]-diff[n];
diff[i] = diff[n];
}
lst -= diff[i];
f0r(j, 2) pq.insert(diff[i]);
ll val = *pq.rbegin();
lst += val;
pq.erase(prev(pq.end()));
}
if (sz(pq) == 0) {
cout << lst << '\n';
return 0;
}
ll cur = *pq.rbegin();
ll slope = 0;
ll bar = diff[n];
pq.erase(prev(pq.end()));
while (sz(pq) && cur >= bar) {
ll nxt = *pq.rbegin();
pq.erase(prev(pq.end()));
if (nxt <= bar) {
lst += (cur - bar) * -slope;
cout << lst << '\n';
return 0;
} else {
lst += (cur - nxt) * -slope;
slope--;
}
}
if (cur <= bar) {
cout << lst << '\n';
return 0;
}
lst += (cur - bar) * -slope;
cout << lst << '\n';
}
