#abc140b

n=int(raw_input())
a=map(int,raw_input().split())
b=map(int,raw_input().split())
c=map(int,raw_input().split())
res=sum(b)
for i in xrange(n-1):
 if a[i+1]==a[i]+1:
  res+=c[a[i]-1]
print res
