require 'prime'

def divisor_count(n)
  return 1 if n == 1
  return 2 if Prime.prime?(n)
  Prime.prime_division(n).map {|e| e[1] + 1 }.inject(:*)
end

n = gets.to_i

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

puts count
