N = gets.strip.to_i
A = gets.strip.split.map(&:to_i)
B = gets.strip.split.map(&:to_i)
C = gets.strip.split.map(&:to_i)
ans=0
(0..N-1).each do |i|
    ans+=B[A[i]-1]
end
t=A[0]
a=C[0]
(1..N-1).each do |i|
    if A[i]-t==1
        ans+=C[t-1]
        #puts t
        #puts C[t]
    end


    t=A[i]
    a=C[i]
end

puts ans
