N = gets[0].to_i
A = gets.split(' ').map(&:to_i)
B = gets.split(' ').map(&:to_i)
C = gets.split(' ').map(&:to_i)
sum = 0
B_index_last = -1

for index in 0..N-1 do
  B_index = A[index] - 1
  sum += B[B_index]
  if B_index_last == -1 
    B_index_last = B_index
    next
  end
  if B_index - B_index_last == 1
    sum += C[B_index_last]
  end
  B_index_last = B_index
end

puts sum