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
first_flag = true

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

puts sum