fun readLargeInt () =
    valOf (TextIO.scanStream (LargeInt.scan StringCvt.DEC) TextIO.stdIn)


val () =
    let
        val n = readLargeInt ()

        val ans = ((n div 5) + (n div 3)) * 2
    in
        print (LargeInt.toString ans ^ "\n")
    end