n = gets.strip.to_i
count = 0
(1..n - 1).each do |i|
  cc = 0
  (1..i).each do |a|
    if i % a == 0
      b = i / a
      if b == a
        count += (cc * 2) + 1
        break
      elsif b < a
        count += cc * 2
        break
      end
      cc += 1
    end
  end
end

puts count

