let solve n =
  let rec max_for a m =
    if m mod a = 0 then m
    else max_for a (m-1)
  in 
  let for3 = max_for 3 n in
  let for5 = max_for 5 n in
  print_int @@ (for3 / 3) * 2 + (for5 / 5) * 2

let _ =
  let n = int_of_string @@ read_line() in
  solve n