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


val () =
    let
        val a = readInt ()
        val b = readInt ()
        val c = readInt ()
        val d = readInt ()
        val s = readInt ()

        val ans = if a * c + b * d <= s then "Yes"
                  else "No"
    in
        print (ans ^ "\n")
    end