#include <bits/stdc++.h>
using namespace std;
char _;
long long i = 0, j = 0, k = 0, a, b, c, d, e, f, g, h, l, m, n, o, p, q, r, s,
          t = 1, u, v, w, x, y, z, maxx = INT_MIN, minn = INT_MAX, ans = 0,
          sum = 0, cnt = 0;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cin >> n;
  long long A[n], B[n], C[n - 1];
  for (long long i = 0; i < (n); i++) {
    cin >> A[i];
  }
  for (long long i = 0; i < (n); i++) {
    cin >> B[i];
  }
  for (long long i = 0; i < (n - 1); i++) {
    cin >> C[i];
  }
  for (long long i = 0; i < (n); i++) {
    if (i > 0) {
      ans += C[i - 1];
      ans += B[i];
    } else {
      ans += B[i];
    }
  }
  cout << ans << endl;
  return 0;
}
