#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define mp make_pair
#define all(a) a.begin(),a.end()
#define sz(a) (int)(a.size())
#define lb lower_bound
#define ub upper_bound
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
#define MOD (ll)(1e9+7)
#define INF (ll)(1e18)
#define debug(...) fprintf(stderr, __VA_ARGS__),fflush(stderr)
#define time__(d) for(long blockTime = 0; (blockTime == 0 ? (blockTime=clock()) != 0 : false);\
debug("%s time : %.4fs\n", d, (double)(clock() - blockTime) / CLOCKS_PER_SEC))
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> PII;
typedef pair<int,int> pii;
typedef vector<vector<int>> vii;
typedef vector<vector<ll>> VII;
int main()
{
owo
int n;
cin>>n;
ll d = 0;
priority_queue<ll>q;
q.push(0);
vector<int>a(n),b(n);
for(int i=0;i<n;i++)cin>>a[i]>>b[i];
ll p = 0; //dp value of the optimum point
for(int i=0;i<n;i++){
d+=a[i] - b[i];
ll dt = d;
if(d<0){
p-=dt;
dt=0;
}
if(dt > q.top())q.push(dt);
else{
p+=q.top() - dt;
q.pop();
q.push(dt);
q.push(dt);
}
}
ll m = 0;
//we want the dp value at point d
//y = mx+c;
//y = (m-1)x + c1
//c1 = c + x
//c here is just p so we pop and add until we reach the segment that contains d
while(q.top() > d){
m--;
p+=q.top();
q.pop();
}
cout<<d*m + p;
}
