N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

cnt = sum(B)

for i in range(N-1):
  if A[i] < A[i+1]:
    s = A[i]-1
    cnt = cnt + C[s]
  
print(cnt)