n = gets.chomp.to_i
array_a = gets.split(" ").map(&:to_i)
array_b = gets.split(" ").map(&:to_i)
array_c = gets.split(" ").map(&:to_i)

satisfaction = 0

n.times do |i|
    satisfaction += array_b[(array_a[i]-1)]
    if array_a[i] + 1 == array_a[i+1]
        satisfaction += array_c[(array_a[i]-1)]
    end
end

puts satisfaction