#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, arr[200005];
  scanf("%lld", &n);
  for (int i = 1; i <= 2 * n; i++) scanf("%lld", &arr[i]);
  arr[0] = 0;
  for (int i = 2; i <= n; i++) {
    if (n + i - 2 != n)
      arr[i] += max(arr[n + i - 1], arr[n + i - 2]);
    else
      arr[i] += arr[n + i - 1];
    arr[n + i] += max(arr[i - 1], arr[i - 2]);
  }
  cout << max(arr[n], arr[n + n]);
}
