MOD = 10 ** 9 + 7
N = gets.to_i
A = gets.split.map(&:to_i)
B = gets.split.map(&:to_i)

a_sum = A.sum
b_sum = B.sum

C = A.zip(B)
C.sort_by! { |a, b| (b - 1.0) / a }
C.reverse!

ans = 0
level = 1

C.each do |a, b|
  ans += level * a
  ans %= MOD
  level *= b
end

puts ans