N=int(input())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
C=list(map(int,input().split()))
s=0
for i in range(0,N):
  s+=B[A[i]-1]
  if i>=1 and A[i]==A[i-1}+1:
    s+=C[i-1]
print(s)