require 'prime'

class Integer
  def my_divisor_list
    return [1] if self == 1
    Prime.prime_division(self).map do |e|
      Array.new(e[1]+1).map.with_index do |element, i|
        e[0]**i
      end
    end.inject{|p,q| p.product(q)}.map do |a|
      [a].flatten.inject(&:*)
    end.sort
  end
end

n = gets.to_i

# def divisor(num)
#   result = []
#   i = 1
#   while i <= num do
#     remainder = num % i
#     if remainder == 0
#       result << i
#     end
#     i += 1
#   end
#   return result
# end

count = 0
for i in (1..n-1) do
  count += (n-i).my_divisor_list.length
end

puts count