#include <bits/stdc++.h>
using namespace std;
// dp[i][j] = min cost to get a[k] >= b[k] for all k <= i
// and (sum (a[k] - b[k]) over k <= i) <= j
// f_i(j) := dp[i][j] is decreasing and convex in j
int main() {
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
vector<pair<int, int>> ab(n);
for (auto& [a, b] : ab) {
cin >> a >> b;
}
vector<int> differences(n);
for (int i = 0; i < n; ++i) {
const auto& [a, b] = ab[i];
differences[i] = a - b;
}
vector<int64_t> prefix_sums(n + 1);
for (int i = 0; i < n; ++i) {
prefix_sums[i + 1] = prefix_sums[i] + differences[i];
}
// looking for a non-decreasing sequence of prefix sums
// with smallest possible sum of absolute differences
// same problem but cannot modify prefix_sums[0]=0 and prefix_sums[n]
// same as saying there are infinitely many breakpoints at 0
int64_t value{0};
priority_queue<int64_t> slope;
for (int i = 1; i < n; ++i) {
slope.push(prefix_sums[i]);
slope.push(prefix_sums[i]);
value += max<int64_t>(0, slope.top()) - prefix_sums[i];
if (slope.top() > 0) {
slope.pop();
}
}
while (!slope.empty()) {
value += max<int64_t>(0, slope.top() - prefix_sums[n]);
slope.pop();
}
cout << value << '\n';
}
