N = int(raw_input())
A = map(int,raw_input().split())
B = map(int,raw_input().split())
C = map(int,raw_input().split())
ans = 0

for i in range(0,N):
  ans = ans + B[A[i]-1]
  if i>0 and A[i-1]+1==A[i]:
    ans = ans + C[A[i-1]-1]

print ans
