N = gets.to_i
A = gets.split(" ")
B = gets.split(" ")
C = gets.split(" ")

score = 0
a_before = 0
A.each do |a|
  a = a.to_i
  score = score + B[a-1].to_i

  if a == a_before + 1
    score = score + C[a-2].to_i
  end 
  a_before = a
end

puts score