import java.util.Scanner;
public class Yuki221{
	public static void main(String[] arg){
		Scanner sc = new Scanner(System.in);
		double n,res;
		n = (double)100*sc.nextDouble();
		res = ((((double)1000000-n)/((double)1000000))*0.01)/((((double)1000000-n)/((double)1000000))*0.01+(n/((double)1000000))*0.99);
		System.out.println(res*(double)100);
	}
}