# require "prime"
n = gets.chomp.to_i
# zenbu = 0
# (1..n-1).each do |c|
#     ans = n - c
#     count = 1
#     if ans >= 2
#     all = ans.prime_division
#         all.each do |i|
#             count *= (i[1]+1)
#         end
#     else
#         count = 1
#     end
#     zenbu += count
# end
# puts zenbu
count = 0
ans = 0
(1..n).each do |a|
    kizyun = n - 1
    kosuu = kizyun / a
    ans += kosuu
end
puts ans