N = readline.to_i
A = readline.split(' ').map {|x| x.to_i - 1}
B = readline.split(' ').map(&:to_i)
C = readline.split(' ').map(&:to_i)

ans = 0
prev = -2
A.each do |a|
  ans += B[a]
  ans += C[prev] if prev == a-1
  prev = a
end
puts ans

