#include <bits/stdc++.h>

using namespace std;
#define IOS ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr)
#define rep(a, b, c) for(int (a)=(b);(a)<=(c);(a)++)
#define per(a, b, c) for(int (a)=(b);(a)>=(c);(a)--)
#define mset(var, val) memset(var,val,sizeof(var))
#define ll long long
#define int ll
#define fi first
#define se second
#define no "NO\n"
#define yes "YES\n"
#define pb push_back
#define endl "\n"
#define pii pair<int,int>
#define pll pair<ll,ll>
#define dbg(x...) do{cout<<#x<<" -> ";err(x);}while (0)

void err() { cout << '\n'; }

template<class T, class... Ts>
void err(T arg, Ts... args) {
    cout << arg << ' ';
    err(args...);
}

const int N = 1000 + 5;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int P = 1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1.0);

int suf[N],a[N],b[N],aa[N],bb[N],c[N];
pii dp[N];//fi val;se shengyu

void solve() {
    int n;
    cin>>n;
    rep(i,1,n){
        cin>>a[i];
    }
    rep(i,1,n){
        cin>>b[i];
    }
    int sum=b[1];
    aa[1]=b[1];
    bb[1]=b[1]+a[1];
    rep(i,2,n){
        sum+=b[i];
        aa[i]=max(bb[i-1],sum);
        bb[i]=aa[i]+a[i];
    }
    suf[0]=suf[n+1]=0;
    per(i,n,1){
        suf[i]=suf[i+1]+(aa[i]-bb[i-1]);
    }
//    suf[1]=0;
    rep(i,1,n) {
        c[i] = min(b[i], suf[i]);
    }
    c[1]=0;
    dp[n].fi=min(suf[n],c[n]),dp[n].se=max(0ll,suf[n]-c[n]);
//    dbg(n,dp[n].fi,suf[n],c[n]);
    per(i,n-1,1){
//        dp[i].fi=min(suf[i],c[i]),dp[i].se=max(0ll,suf[i]-c[i]);
//        dbg(suf[i],c[i],dp[i].fi,dp[i].se);
        dp[i].fi=dp[i+1].fi,dp[i].se=dp[i+1].se+suf[i]-suf[i+1];
//        dbg(i,dp[i].fi,dp[i].se);
        rep(j,i+2,n){
            if(dp[i].fi<=dp[j].fi+min(dp[j].se+suf[i]-suf[j],c[i])){
                if(max(0ll,dp[j].se+suf[i]-suf[j]-c[i])>=dp[i].se){
                    dp[i].se=max(0ll,dp[j].se+suf[i]-suf[j]-c[i]);
                }
                dp[i].fi=dp[j].fi+min(dp[j].se+suf[i]-suf[j],c[i]);
            }
//            dbg(i,j,dp[i].fi,dp[i].se);
        }
//         dbg(i,dp[i].fi,dp[i].se);
//        cout<<endl;
    }
    cout<<bb[n]-dp[1].fi<<endl;
}

signed main() {
    IOS;
    int T = 1;
//    cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}
/*
100
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
6 1 10 10 5 1 9 8 6 7 5 5 4 6 10 5 6 7 3 8 6 3 3 9 3 6 2 9 7 10 8 5 4 8 5 6 8 5 1 4 4 6 4 4 6 8 9 3 1 3 9 6 6 4 6 8 10 6 2 1 3 8 3 3 5 10 6 5 8 8 1 8 5 7 10 3 5 2 9 8 2 3 3 3 8 7 7 10 5 6 7 4 8 1 9 9 5 7 7 8

7
1 1 1 1 1 1 1
6 10 5 6 7 3 8

*/