#include <bits/stdc++.h>
using namespace std;
long long day[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const long long MOD = 1000000007LL;
bool isupper(char c) {
  if ('A' <= c && c <= 'Z') return 1;
  return 0;
}
bool islower(char c) {
  if ('a' <= c && c <= 'z') return 1;
  return 0;
}
bool iskaibun(string s) {
  for (long long i = 0; i < s.size() / 2; i++)
    if (s[i] != s[s.size() - i - 1]) return 0;
  return 1;
}
bool isnumber(char c) { return ('0' <= c && c <= '9'); }
bool isalpha(char c) { return (isupper(c) || islower(c)); }
template <typename T>
void print(vector<T> v) {
  for (long long i = 0; i < v.size(); i++) {
    if (i) cout << " ";
    cout << v[i];
  }
  cout << endl;
}
long long INF = 1e18;
template <typename T>
void printendl(vector<T> v) {
  for (auto date : v) cout << date << endl;
}
template <typename T>
void printvv(vector<vector<T>> v) {
  for (long long i = 0; i < v.size(); i++) {
    for (long long j = 0; j < v[i].size(); j++) {
      if (j) cout << " ";
      cout << v[i][j];
    }
    cout << endl;
  }
}
long long gcd(long long a, long long b) {
  if (a < b) swap(a, b);
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
struct Edge {
  long long to, cost;
};
signed main() {
  long long n;
  cin >> n;
  vector<vector<long long>> v(2, vector<long long>(n)),
      dp(3, vector<long long>(n + 1));
  for (long long i = (long long)0; i < (long long)2; i++)
    for (long long j = (long long)0; j < (long long)n; j++) cin >> v[i][j];
  priority_queue<long long, vector<long long>> p[2];
  for (long long i = 0; i < n; i++) {
    if (i == 0) {
      p[0].push(v[0][i]);
      p[1].push(v[1][i]);
      continue;
    }
    long long f1 = p[0].top();
    long long f2 = p[1].top();
    p[0].push(v[0][i] + f2);
    p[1].push(v[1][i] + f1);
  }
  cout << max(p[0].top(), p[1].top()) << endl;
}
