package recursion1.Assignment;

import java.util.Scanner;

/*Given k, find the geometric sum i.e.

1 + 1/2 + 1/4 + 1/8 + ... + 1/(2^k)

using recursion.

Input format :

Integer k

Output format :

Geometric sum

Constraints :

0 <= k <= 1000

Sample Input 1 :

3

Sample Output 1 :

1.875

Sample Input 2 :

4

Sample Output 2 :

1.93750*/

public class GeometricSum {

public static double geometricSum(int k) {

if (k == 0) {

return 1;

}

return (geometricSum(k - 1) + 1 / Math.pow(2, k));

}

public static void main(String[] args) {

Scanner scan = new Scanner(System.in);

int k = scan.nextInt();

System.out.println(geometricSum(k));

}

}