#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]);
    per(i,n-1,1){
        int mx=0;
        dp[i].fi=min(suf[i],c[i]),dp[i].se=max(0ll,suf[i]-c[i]);
        if(dp[i+1].fi>dp[i].fi){
            dp[i].fi=dp[i+1].fi,dp[i].se=dp[i+1].se;
        }
        per(j,n,i+2){
            if(dp[i].fi<=dp[j].fi+min(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]);
                dp[i].se=max(0ll,dp[j].se+suf[i]-suf[j]-c[i]);
            }
        }
//         dbg(i,dp[i].fi);
    }
    cout<<bb[n]-dp[1].fi<<endl;
}

signed main() {
    IOS;
    int T = 1;
//    cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}
/*
4
1 1 1 1
6 4 4 4

*/