N = int(input())

s0 = list(map(int,input().split()))

s1 = list(map(int,input().split()))

s2 = list(map(int,input().split()))

sum1 = sum(s1)

for i in range(N):
  if (s0[i]+1) == s0[i+1]:
    sum1 += s2[s0[i]-1]
  else :
    sum1=sum1

print(sum1)