N = gets.to_i

sum_combi = 0
(1..N-1).each do |j|
  if N - j == Integer.sqrt(N - j) ** 2 # 平方数か？
    sum_combi += (1..Integer.sqrt(N - j)).select{ |i| (N - j) % i == 0 }.length * 2 - 1
  else 
    sum_combi += (1..Integer.sqrt(N - j)).select{ |i| (N - j) % i == 0 }.length * 2 
end

puts sum_combi