#include <bits/stdc++.h>
using namespace std;
struct Line {
long long m, c;
Line() {}
Line(long long mm, long long cc) : m(mm), c(cc) {}
inline long long getY(long long x) { return m*x+c; }
};
const int N = (int)5e5;
int n, a[N], b[N];
long long d[N];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
for (int i = 0;i < n;i ++) {
cin >> a[i] >> b[i];
d[i] = a[i] - b[i];
if (i != 0) d[i] += d[i - 1];
}
Line line;
priority_queue<int> pq;
if (d[0] > 0) {
pq.push(d[0]);
line = Line(-1, d[0]);
} else {
line = Line(0, -d[0]);
}
for (int i = 1;i < n - 1;i ++) {
if (d[i] >= 0) {
pq.push(d[i]);
pq.push(d[i]);
pq.pop();
line.m --;
line.c += d[i];
} else {
if (line.m + 1 > 0) {
line.m = 0;
line.c += -d[i];
while ((int)pq.size()) pq.pop();
} else {
line.m ++;
line.c += -d[i];
pq.pop();
}
}
}
vector<int> val;
while ((int)pq.size()) {
val.push_back(pq.top());
pq.pop();
}
sort(val.begin(), val.end());
for (auto& e : val) {
if (e >= d[n - 1]) break;
long long y = line.getY(e);
line.m ++;
line.c = y - line.m * e;
}
cout << line.getY(d[n - 1]) << '\n';
return 0;
}
