let ( +@ ) = Int64.add
let ( -@ ) = Int64.sub
let ( *@ ) = Int64.mul
let ( /@ ) = Int64.div

let () =
  let n = read_line () |> Int64.of_string in
  let fb = n /@ (Int64.of_int 15) in
  let f = (n /@ (Int64.of_int 3)) -@ fb
  and b = (n /@ (Int64.of_int 5)) -@ fb
  in
  let ans = (fb *@ (Int64.of_int 4)) +@ ((f +@ b) *@ (Int64.of_int 2)) in
  print_endline (Int64.to_string ans)