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

val () =
    let
        val n = readInt ()

(*
        ((10000 - N) * 0.01) / ((10000 - N) * 0.01 + N * 0.99)
*)
        val ans = (Real.fromInt (10000 - n) / (Real.fromInt (10000 + 98 * n))) * 100.0
    in
        print ((Real.fmt (StringCvt.FIX (SOME 4)) ans) ^ "\n")
    end