#include <iostream>
#include <queue>
#define ll long long
using namespace std;
/*
Transform the array into A - B
We could change an operation into -1 +1 adjacent indices
Transform the array into prefix sum
Now, an operation changed A[i] into A[i] + 1 or A[i] - 1
for 1 <= i < N. A[0] = 0, A[N] = SUM;
Therefore the array must be transformed such that it is non-decreasing
We can achieve this with slope trick.
*/
const ll INF = 1e18;
int n;
ll ar[500001], res = 0;
priority_queue<ll> pq;
int main()
{
ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 0; i < n; i++)
{
int a, b; cin >> a >> b;
ar[i] = a - b;
if (i) ar[i] += ar[i - 1];
}
pq.push(0);
for (int i = 0; i < n - 1; i++)
{
if (ar[i] < pq.top())
{
res += pq.top() - ar[i]; pq.pop();
pq.push(max(ar[i], 0LL));
}
// cout << "Push at " << ar[i] << "\n";
pq.push(max(ar[i], 0LL));
}
int i;
ll pv = pq.top();
for (i = 0; pq.top() > ar[n - 1]; i++)
{
res += (pv - pq.top()) * i;
pv = pq.top(); pq.pop();
}
res += (pv - ar[n - 1]) * i;
cout << res << "\n";
return 0;
}
