# https://atcoder.jp/contests/abc140/tasks/abc140_b

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

ans = 0
for i in range(N):
    ans += B[A[i]-1]
    if i > 0 and A[i] == A[i-1] + 1:
        ans += C[A[i]-2]

print(ans)
