fun member x nil = false
  | member x (h::tl) =
    if x = h
    then true
    else member x tl


fun readInt () =
    valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn)

exception Dummy
fun findAnsAux nil _ _ = raise Dummy
  | findAnsAux _ nil _ = raise Dummy
  | findAnsAux (h::tl) (dh::dtl) target =
    if h = target then dh
    else dh + findAnsAux tl dtl target


fun findAns location target =
    let
        val mapped =
            List.map
                (fn x => x + location)
                [2, 4, 3, 2, 4, 3, 2]
    in
        if member target mapped then findAnsAux mapped [2, 2, 1, 1, 2, 1, 1] target
        else (2 + 2 + 1 + 1 + 2 + 1 + 1) + findAns (List.last mapped) target
    end

val () =
    let
        val x = readInt ()
        
                                 
        val ans = findAns 0 x
    in
        print (Int.toString ans ^ "\n")
    end