require 'prime'

class Integer
  def divisor_count
    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.length
  end
end

n = gets.to_i

count = 0
for i in 1..n-1 do
  count += i.divisor_count
end

puts count