import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        int Chisl, Znam, I, N;
        double Sum;
        System.out.println("Введте значение N");
        Scanner num_N = new Scanner(System.in);
        int N = num_N.nextInt();
        Sum = (0.5);
        Chisl = 1;
        Znam = 2;
        for ( I = 2; I <= N; I++) {
            Znam = Znam * 2;
            Sum = Sum + (Chisl / Znam);
        }
    }   System.out.println("Sum = "+Sum);
}