#include<bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// template<class T> using Tree = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimization("unroll-loops")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC optimize("fast-math")
// #pragma GCC optimize("no-stack-protector")
// #define ll __int128
// #define ll long long
#define ll int
#define f(i,a,b) for(ll i=a;i<b;i++)
#define mod 1000000007
// #define mod 998244353 
#define mp make_pair
#define uniq(v) (v).erase(unique(all(v)),(v).end())
#define ff first
#define ss second
#define rf(i,a,b) for(ll i=a;i>=b;i--)
#define sc(a) scanf("%lld",&a)
#define pf printf
#define sz(a) (int)(a.size())
#define psf push_front
#define ppf pop_front
#define ppb pop_back
#define pb push_back
#define pq priority_queue
#define all(s) s.begin(),s.end()
#define sp(a) setprecision(a)
#define rz resize
#define ld long double
#define inf (ll)1e18
#define ub upper_bound
#define lb lower_bound
#define bs binary_search
#define eb emplace_back
const double pi = acos(-1);
ll binpow(ll a, ll b){ll res=1;while(b!=0){if(b&1)res*=a;a*=a;b>>=1;}return res;}
ll binpow(ll a, ll b, ll md){ll res=1;a%=md;if(a==0)return 0;while(b!=0){if(b&1)res*=a,res%=md;a*=a,a%=md;b>>=1;}return res%md;}
 
using namespace std;

ll n,l,r,mid,ans;
vector<ll> a,d;

vector<multiset<pair<ll,ll> > > arr;

void merge(multiset<pair<ll,ll> > &a, multiset<pair<ll,ll> > &b)
{
    for(auto temp:b)
        a.insert(temp);
}
 
int main()
{
    ios_base::sync_with_stdio(false);
    // freopen("xortransform.in","r",stdin);
    // freopen("xortransform.out","w",stdout);
     #ifndef ONLINE_JUDGE
         freopen("input.txt","r",stdin);
         freopen("output.txt","w",stdout);
     #endif
    int z=1;
    // cin>>z;
    f(ilu,1,z+1)
    {
        // cout<<"Case #"<<ilu<<": ";
        cin>>n;
        a.rz(n),d.rz(n),arr.rz(n);
        r=0,l=1e9;
        f(i,0,n)
            cin>>a[i],r=max(r,a[i]),l=min(l,a[i]);
        f(i,0,n)
            cin>>d[i];

        f(i,0,n)
        {
            ll lid=max(0,i-d[i]),duri=i+d[i];
            arr[lid].insert(mp(duri,a[i]));
        }

        while(l<=r)
        {
            mid=(l+r)/2;    

            multiset<pair<ll,ll> > s;
			int flag=1;

			f(i,0,n)
			{

				merge(s,arr[i]);
			
				ll rem=mid;
				while(sz(s) && rem>0)
				{
					auto temp=(*s.begin());
					ll duri=temp.ff,c=temp.ss;
					s.erase(s.begin());
					if(duri<i){
						flag=0;
						break;
					}
					ll sub=min(rem,c);
					rem-=sub,c-=sub;
					if(c)
						s.insert(mp(duri,c));
				}
			}

            if((!sz(s)) && flag)
                ans=mid,r=mid-1;
            else
                l=mid+1;
        }

        cout<<ans;
    }
}