fun main (args : Array<String>) {
	val n = readLine()
	val N : Double = n!!.toDouble()
	var count : Double = 0.0
	var result : Double = 0.0
	for (i in 1..N.toInt()) {
		if (i % 2 == 1) {
			count += 1.0
		}
	}
	result = count / N
	println("${result}")
}