#include <bits/stdc++.h>
using namespace std;
int n, a, b, c;
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a;
  }
  for (int i = 0; i < n; i++) {
    cin >> a;
    b += a;
  }
  for (int i = 0; i < n - 1; i++) {
    cin >> a;
    b += a;
    c = max(a, c);
  }
  cout << b;
}
