#include <bits/stdc++.h>
int main() {
  int N, i, j, k;
  scanf("%d", &N);
  int A[N];
  int B[N];
  int C[N - 1];
  for (i = 1; i <= N; i++) {
    scanf("%d", &A[i]);
  }
  for (j = 1; j <= N; j++) {
    scanf("%d", &B[j]);
  }
  for (k = 1; k <= N - 1; k++) {
    scanf("%d", &C[k]);
  }
  if (j = i + 1)
    printf("%d", A[i] + B[j] + C[i]);
  else
    printf("%d", A[i] + B[j]);
  return 0;
}
