import java.io.BufferedReader import java.io.InputStream import java.io.InputStreamReader import java.io.PrintWriter import java.lang.StringBuilder import java.util.* fun PrintWriter.solve(sc: FastScanner) { val p = sc.nextDouble() println(p / (1.0 - p)) } fun main(args: Array) { val writer = PrintWriter(System.out, false) writer.solve(FastScanner(System.`in`)) writer.flush() } class FastScanner(s: InputStream) { private var st = StringTokenizer("") private val br = BufferedReader(InputStreamReader(s)) fun next(): String { while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine()) return st.nextToken() } fun nextInt() = next().toInt() fun nextLong() = next().toLong() fun nextLine() = br.readLine() fun nextDouble() = next().toDouble() fun ready() = br.ready() }