N = gets.to_i
A = gets.split.map(&:to_f)
B = gets.split.map(&:to_f)

ans = 0.0
N.times do |i|
    a, b = A[i], B[i]
    x1 = Math.sqrt([1, a / b].max)
    ans += a / x1 + b * x1
end

puts ans