N = int(input())
A = [int(i) for i in input().split()]
B = [int(i) for i in input().split()]
C = [int(i) for i in input().split()]

score = 0

for n in range(N):
    a = A[n]
    b_index = a-1
    score = score + B[b_index]

    if b_index -1 > -1:
        if A[n-1] + 1 == a:
            score = score + C[a-2]

print(score)