n = gets.to_i
num = 0

for i in 1..n do
  if i % 3 == 0 && i % 5 == 0
    #"FizzBuzz" 
    num += 4
  elsif i % 3 == 0
    #"Fizz"
    num += 2
  elsif i % 5 == 0
    #"Buzz"
    num += 2
  end
end

puts num