n = int(input())
a = list(map(int,input().split()))
b = list(map(int,input().split()))
c = list(map(int,input().split()))
p = 0
ans = 0
for i in a:
  i -= 1
  ans += b[i]
  if i>0 and i-p == 1:
    ans += c[p]
  p = i
print(ans)
    