#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

long long n, time=0, xp=0;

struct erc
{
    long long kuszob, db;
};

bool cmp (erc a, erc b)
{
    return a.kuszob < b.kuszob;
}
vector<erc> lista;
int main()
{
    cin>>n;
    lista.resize(n);

    for(int i=0; i<n; i++)        ///beolvas
    {
        cin>>lista[i].kuszob;
    }
    for(int i=0; i<n; i++)
    {
        cin>>lista[i].db;
    }                           ///idaig

    int i=0, j=n-1;
    sort(lista.begin(), lista.end(), cmp);
    while (i != j)
    {
        if(xp >= lista[i].kuszob)
        {
            xp+=lista[i].db;
            time+=lista[i].db;
            i++;
        }
        else
        {
            if(lista[i].kuszob - xp < lista[j].db)
            {
                long long need = lista[i].kuszob - xp;
                lista[j].db -= need;
                xp += need;
                time += 2 * need;
            }
            else if (lista[i].kuszob - xp == lista[j].db)
            {
                xp+=lista[j].db;
                time+=2*lista[j].db;
                j--;
            }
            else
            {
                xp+=lista[j].db;
                time+=2*lista[j].db;
                j--;
            }
        }
    }
    while(lista[i].db >0)
    {
        if(xp<lista[i].kuszob)
        {
            xp++;
            time+=2;
        }
        else
        {
            xp++;
            time++;
        }
        lista[i].db--;
    }
    cout << time;
    return 0;
}