#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define Pint pair<int,int>
#define Pll pair<ll,ll>
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<n;i++)
#define all(v) v.begin(),v.end()
#define pb push_back
#define eb emplace_back
template<class T>void chmax(T &a,T b){if(a<b)a=b;}
template<class T>void chmin(T &a,T b){if(a>b)a=b;}
constexpr int INF=1000000000;
constexpr ll llINF=1000000000000000000;
constexpr int mod=1000000007;
constexpr double eps=1e-8;
const double pi=acos(-1);
int dx[]={0,1,0,-1},dy[]={1,0,-1,0};
int Random(int mi,int ma){
    random_device rnd;
    mt19937 mt(rnd());//32bit
    //[mi,ma]
    uniform_int_distribution<int>engine(mi,ma);
    return engine(mt);
}
ll gcd(ll a,ll b){
    if(b==0)return a;
    return gcd(b,a%b);
}
ll lcm(ll a,ll b){
    return a/gcd(a,b)*b;
}
bool prime(int a){
    if(a==1)return false;
    for(int i=2;i*i<=a;i++){
        if(a%i==0)return false;
    }
    return true;
}
ll modpow(ll a,ll b){
    if(b==0)return 1;
    if(b%2)return modpow(a,b-1)*a%mod;
    ll memo=modpow(a,b/2);
    return memo*memo%mod;
}
vector<ll>kaijo,invkaijo;
void init_fact(int n){
    kaijo.resize(n+1);
    invkaijo.resize(n+1);
    kaijo[0]=1;
    for(ll i=1;i<=n;i++){
        kaijo[i]=kaijo[i-1]*i;
        kaijo[i]%=mod;
    }
    rep(i,n+1)invkaijo[i]=modpow(kaijo[i],mod-2);
}
vector<vector<ll>>C,sC;
void init_comb(int n,int m){
    C.resize(n+1,vector<ll>(m+1,0));
    sC.resize(n+1,vector<ll>(m+1,0));
    C[0][0]=1;
    for(int i=1;i<=n;i++){
        C[i][0]=1;
        for(int j=1;j<=m;j++){
            C[i][j]=(C[i-1][j-1]+C[i-1][j])%mod;
        }
    }
    rep(i,n+1){
        rep(j,m){
            sC[i][j+1]=(sC[i][j]+C[i][j])%mod;
        }
    }
}
ll comb(int a,int b){
    if(a<b)return 0;
    if(a<0||b<0)return 0;
    return kaijo[a]*invkaijo[a-b]%mod*invkaijo[b]%mod;
}
ll inv(ll x){
    x=modpow(x,mod-2);
    return x;
}
int dp[100010];
void solve(){
    int n;
    cin>>n;
    vector<ll>a(n),b(n),c,d;
    rep(i,n)cin>>a[i];
    rep(i,n)cin>>b[i];
    ll ans=0;
    for(int i=0;i<n;i+=2){
        ans+=max(a[i]+a[i+1],b[i+1]+b[i]);
        if(a[i]+a[i+1]>=b[i]+b[i+1]){
            c.pb(b[i]-a[i]);
            d.pb(b[i+1]-a[i+1]);
        }
        else{
            c.pb(a[i+1]-b[i+1]);
            d.pb(a[i]-b[i]);
        }
    }
    sort(all(d));
    sort(all(c));
    rep(i,c.size()){
        if(c[i]+d[i]>=0)ans+=c[i]+d[i];
    }
    cout<<ans<<endl;
}
int main(){
    cin.tie(0);ios::sync_with_stdio(false);
    //int t;cin>>t;while(t--)
    solve();
    return 0;
}
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define per(i, a, b) for (int i = a; i >= b; i--)
const int inf = 0x3f3f3f3f;
const int mod = 1e9 + 7;
typedef long long LL;
typedef pair <int, int> P;
const int N = 2e5 + 5;

int n, a[N], b[N], c[N];
LL ans, res;

int main() {
	cin>>n;
	rep (i, 1, n) scanf("%d", &a[i]), ans += a[i];
	rep (i, 1, n) scanf("%d", &b[i]), b[i] -= a[i];
	rep (i, 1, n) {
		if (i&1) b[(i + 1)>>1] = b[i];
		else c[i>>1] = b[i]; 
	} 
	sort(b + 1, b + n/2 + 1);
	sort(c + 1, c + n/2 + 1);
	res = ans;
	per (i, n/2, 1) res += b[i] + c[i], ans = max(ans, res);
	printf("%lld\n", ans);
}
