n = gets.to_i
pre_sieve = Array.new(n) { |i| i }
sieve = Array.new(n)
ans = 0

s = Math.sqrt(n - 1).to_i
2.upto(s) do |i|
  ((n - 1) / i).times do |j|
    pre_sieve[i * (j + 1)] = i if i < pre_sieve[i * (j + 1)]
  end
end

2.upto(n - 1) do |i|
  h = Hash.new(0)
  x = i
  while x != 1
    h[pre_sieve[x]] += 1
    x /= pre_sieve[x]
  end
  sieve[i] = h
end

2.upto(n - 1) do |i|
  x = 1
  sieve[i].each_value do |j|
    x *= (j + 1)
  end

  ans += x
end

puts ans + 1
