#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
struct Slope{
int val; // val at x = 0
int slope; // slope at x = 0
multiset<int>s;
Slope(int val, int slope, vector<int>vals) : val(val), slope(slope){
for(int nxt: vals){
s.insert(nxt);
}
}
Slope(){
}
vector<int> getSlopes(){
vector<int>ans;
for(int nxt: s){
ans.push_back(nxt);
}
return ans;
}
};
signed main() {
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
vector<int>a(n+1);
int ans = 0;
for(int i = 1; i<=n; i++){
int x,y;
cin >> x >> y;
a[i] = x-y;
a[i] += a[i-1];
}
for(int i = 1; i<=n; i++){
if(a[i] < 0){
ans -= a[i];
a[i] = 0;
}
}
int pt = a[n];
vector<Slope>s(n+1);
for(int i = 1; i<=n; i++){
s[i] = Slope(a[i],-1,{a[i],a[i]});
}
Slope t = s[1];
// cerr << t.s.size() << '\n';
t.s.erase(--t.s.end());
// cerr << "hi\n";
for(int i = 2; i<=n; i++){
t.val += s[i].val;
t.slope--;
for(int nxt: s[i].s){
t.s.insert(nxt);
}
t.s.erase(--t.s.end());
}
// cerr << "hi\n";
int cur = 0;
int val = t.val;
int slope = t.slope;
for(int nxt: t.s){
if(nxt > pt){
break;
}
val+= slope*(nxt-cur);
cur = nxt;
slope++;
}
val += slope * (pt - cur);
cout << val + ans << '\n';
return 0;
}
