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#ifdef LOCAL
#  define _GLIBCXX_DEBUG
#else
#  define cerr __get_ce
#endif
#include <bits/stdc++.h>
#define ff first
#define ss second
#define szof(x) ((int)x.size())

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
int const INF = (int)1e9 + 1e3;
ll const INFL = (ll)1e18 + 1e6;
#ifdef LOCAL
	mt19937 tw(9450189);
#else
	mt19937 tw(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif
uniform_int_distribution<ll> ll_distr;
ll rnd(ll a, ll b) { return ll_distr(tw) % (b - a + 1) + a; }


void solve() {
	int n;
	cin >> n;
	vector<vector<int>> inp;
	for (int i = 0; i < 2; ++i) {
		inp.push_back(vector<int>());
		for (int j = 0; j < n; ++j) {
			int num;
			cin >> num;
			inp[i].push_back(num);
		}
	}

	pll d = {0, 0};

	for (int i = 0; i < n; ++i) {
		pll next = {max(d.ff, d.ss + inp[0][i]), max(d.ss, d.ff + inp[1][i])};
		d = next;
	}

	cout << max(d.ff, d.ss) << "\n";
}


int main() {
#ifdef LOCAL
	auto start_time = clock();
	cerr << setprecision(3) << fixed;
#endif
	cout << setprecision(15) << fixed;
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int test_count = 1;
	// cin >> test_count;
	for (int test = 1; test <= test_count; ++test) {
		solve();
	}
	
#ifdef LOCAL
	auto end_time = clock();
	cerr << "Execution time: " << (end_time - start_time) * (int)1e3 / CLOCKS_PER_SEC << " ms\n";
#endif
}