def get_divisor_num(n)
  cnt = 0
  i = 1
  while i < Math.sqrt(n)
    cnt += 1 if n % i == 0
    i += 1
  end
  cnt *= 2
  cnt += 1 if n % Math.sqrt(n) == 0
  return cnt
end

n = gets.to_i

ans = 0
for i in 1..n-1 do
  ans += get_divisor_num(i)
end

puts ans