n = int(input())
a = list(map(int, input().split()))
b = list(map(int, input().split()))
c = list(map(int, input().split()))

sum = b[a[0]-1]
p = a[0]-1
for i in a[1:]:
    index = i-1
    sum += b[index]
    if p != n-1:
        sum += c[p]
    p = index

print(sum)
