#include<bits/stdc++.h>

using namespace std;
#define X first
#define Y second
#define pb push_back
typedef double db;
typedef long long ll;
typedef pair<int,int> P;
const int MAXN=1e5+10;
int n,l[MAXN],r[MAXN];
ll ls,rs,res=0;
priority_queue<ll> L;
priority_queue<ll,vector<ll>,greater<ll> > R;

int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        scanf("%d%d",&l[i],&r[i]);
    L.push(l[1]);R.push(l[1]);
    for(int i=2;i<=n;i++)
    {
        ls-=r[i]-l[i];rs+=r[i-1]-l[i-1];
        ll lb=L.top()+ls,rb=R.top()+rs;
        if(l[i]<lb)
        {
            res+=lb-l[i];R.push(lb-rs);
            L.push(l[i]-ls);L.push(l[i]-ls);L.pop();
        }
        else if(l[i]>rb)
        {
            res+=l[i]-rb;L.push(rb-ls);
            R.push(l[i]-rs);R.push(l[i]-rs);R.pop();
        }
        else
        {
            L.push(l[i]-ls);
            R.push(l[i]-rs);
        }
    }
    printf("%lld",res);
    return 0;
}