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