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

ans = 0
past = 0

for i in range(n):
    ryouri = a[i]-1
    ans += b[ryouri]
    if i >= 1:
      if (ryouri) == (past+1):
        ans += c[i-2]
    past = ryouri
print(ans)
      