io = DATA.eof? ? STDIN : DATA
n=io.gets.to_i

Amax=n
D = Array.new(Amax + 2,0)
D[1]=1
(2 .. n).each do |i|
  s = i
  while s < D.size
    if s==i
      D[s]+=2
    else
      D[s]+=1
    end
    s += i
  end
end
puts D[1..(n-1)].sum

__END__
