require 'prime'

dp = {}

def c_div(i)
  pds = i.prime_division
  rst = 1
  pds.each do |x|
    rst *= (x[1]+1)
  end
  rst
end

n = gets.chomp.to_i
cnt = 0
(n-1).times do |i|
  if (i+1).prime?
    cnt += 2
  else
    cnt += c_div(i+1)
  end
end
puts cnt