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

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

print satisfied
