N = input()
A = list(map(int,input().split()))
B = list(map(int,input().split()))
C = list(map(int,input().split()))
ans = B[A[0]]
for i in range(1, len(A)):
  ans += B[A[i]]
  if A[i - 1] == A[i] - 1:
    ans += C[A[i - 1]]
print(ans)
