n = int(input())
a = input().split()
b = input().split()
c = input().split()

result = 0
j = 1
for i in a:
  m = int(i) - 1
  result += int(b[m])
  if not (m == 1) and (j + 1 == m):
      result += int(c[j])
  j = m
print(result)