
fun main(args: Array<String>) {

    // input
    val (dice, limit) = readLine()?.let { it.split(" ") }!!.map { it.toInt() }
    val sum = (1..dice).map {
        var temp = 1.0 / dice
        var now = it
        while( now < limit ) {
            now *= 2
            temp /= 2
        }
        temp
    }.sum()
    println(sum)


}
