#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define int long long
const int MAXN = 5e5;
const ll inf = 1e18;
int n;
int vals[MAXN];
ll pre[MAXN];
int ben[MAXN];
class stree {
public:
int lp, rp;
stree *l = nullptr;
stree *r = nullptr;
pii mx;
int lz = 0;
stree(int lv, int rv) {
lp = lv;
rp = rv;
if (lp < rp) {
int m = (lp+rp)/2;
l = new stree(lp, m);
r = new stree(m+1, rp);
mx = max(l->mx, r->mx);
}
else {
mx = pii(ben[lp], lp);
}
}
void add_to(int v) {
lz += v;
mx.first += v;
}
void push() {
if (l) {
l->add_to(lz);
r->add_to(lz);
}
lz = 0;
}
void upd(int lv, int rv, int v) {
if (lp > rv || rp < lv) return;
if (lp >= lv && rp <= rv) {
return add_to(v);
}
push();
l->upd(lv, rv, v);
r->upd(lv, rv, v);
mx = max(l->mx, r->mx);
}
pii get_mx(int lv, int rv) {
if (lp > rv || rp < lv) return pii(-1, -1);
if (lp >= lv && rp <= rv) return mx;
push();
return max(l->get_mx(lv, rv), r->get_mx(lv, rv));
}
};
stree *mx_tree;
class stree2 {
public:
int lp, rp;
stree2 *l = nullptr;
stree2 *r = nullptr;
ll mn;
ll sub = 0;
stree2(int lv, int rv) {
lp = lv;
rp = rv;
if (lp < rp) {
int m = (lp+rp)/2;
l = new stree2(lp, m);
r = new stree2(m+1, rp);
mn = min(l->mn, r->mn);
}
else {
if (pre[lp] <= 0) mn = inf;
else mn = pre[lp];
}
}
void erase() {
if (mn) return;
if (lp == rp) {
mn = inf;
mx_tree->upd(0, lp, -2);
return;
}
push();
l->erase();
r->erase();
mn = min(l->mn, r->mn);
}
void add_to(int v) {
mn += v;
sub += v;
if (mn == 0) {
erase();
}
}
void push() {
if (l) {
l->add_to(sub);
r->add_to(sub);
}
sub = 0;
}
void upd(int lv, int rv, int v) {
if (lp > rv || rp < lv) return;
if (lp >= lv && rp <= rv) {
add_to(v);
return;
}
push();
l->upd(lv, rv, v);
r->upd(lv, rv, v);
mn = min(l->mn, r->mn);
}
ll query(int lv, int rv) {
if (lp > rv || rp < lv) return inf;
if (lp >= lv && rp <= rv) return mn;
push();
return min(l->query(lv, rv), r->query(lv, rv));
}
};
stree2 *beat_tree;
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> n;
ll ans = 0;
for (int i = 0; i < n; i++) {
int x, y; cin >> x >> y;
vals[i] = x-y;
pre[i] += vals[i];
if (i < n-1) pre[i+1] = pre[i];
ans += (pre[i] < 0) ? (-pre[i]) : pre[i];
}
for (int i = n-1; i >= 0; i--) {
if (pre[i] <= 0) ben[i]--;
else ben[i]++;
if (i) ben[i-1] = ben[i];
}
mx_tree = new stree(0, n-1);
beat_tree = new stree2(0, n-1);
pii bst = mx_tree->get_mx(0, n-1);
ll rem = pre[n-1];
while (bst.first && rem) {
ll lim = beat_tree->query(bst.second, n-1);
lim = min(lim, rem);
ans -= lim*bst.first;
beat_tree->upd(bst.second, n-1, -lim);
bst = mx_tree->get_mx(0, n-1);
rem -= lim;
}
cout << ans << "\n";
}
