#include "bits/stdc++.h"
using namespace std;

typedef long long ll;



int main (){
ll n;
    cin >> n ;

    vector<ll> v1(n, 0);
    vector<ll> v2(n, 0);

    vector<ll> r1(n, 0);
    vector<ll> r2(n, 0);


    for (int i = 0; i < n; ++i) {
        cin >> v1[i];
    }

    for (int i = 0; i < n; ++i) {
        cin >> v2[i];
    }

    r1[n - 1] = v1[n - 1];
    r2[n - 1] = v2[n - 1];
    for (int i = n - 2; i >= 0; --i) {
        ll t1 = r2[i + 1];
        if (i + 2 < n) {
            t1 = max(t1, r2[i + 2]);
        }
        t1 += v1[i];
        r1[i] = t1;

        ll t2 = r1[i + 1];
        if (i + 2 < n) {
            t2 = max(t2, r1[i + 2]);
        }
        t2 += v2[i];
        r2[i] = t2;
    }
    ll ans = max(r2[0], r1[0]);
    cout << ans;
    return 0;
}