fun main(args: Array<String>) = println(run {
    val (n, k) = readLine()!!.split(" ").map { it.toInt() }

    (1..n).map { dice ->
        var score = dice
        var rate = 1.0
        while(score < k) {
            score*=2
            rate*=0.5
        }
        rate
    }.average()
})