n = gets.to_i
a = [nil] + gets.split.map(&:to_i)
b = [nil] + gets.split.map(&:to_i)
c = [nil] + gets.split.map(&:to_i)
s = 0
i = 1
prev = nil
while i < n+1
  s += b[a[i]]
  s += c[prev] if prev && a[i] == prev + 1
  prev = a[i]
  i += 1
end
p s
