# util functions

# debug
$debugFlag = ( ARGV[0] != nil )
p "==== DEBUG MODE ====" if $debugFlag

def pd(str)
  p str if $debugFlag
end

def printd(str)
  print str if $debugFlag
end

# input
inputs = []
lc = 0
while l = $stdin.gets do
  if false
    inputs << l.chomp.split(" ").map(&:to_s)
  else
    inputs << l.chomp.split(" ").map(&:to_i)
  end
  lc += 1
end

# input check
if $debugFlag
  p "--- INPUT (begin) ---"
  inputs.each do |l_i|
    p l_i
  end
  p "--- INPUT (end) ---"
  print "\n"
end

as = inputs[1]
bs = inputs[2]
cs = inputs[3]

# body
if $debugFlag
  p as
  p bs
  p cs
end

ans = 0
as.length.times do |i|
  ans += bs[as[i]-1]
  if i >= 1
    if as[i]-1 == as[i-1]-1 + 1
      ans += cs[as[i-1]-1]
    end
  end
end

puts ans
