View Code of Problem 71

import  java.util.*;
public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		 int n = sc.nextInt();
		 double a = 1; 
		 double b = 2; 
		 double sum = 0;
		 for (int i = 0; i < n; i++) {
			sum += b/a;
			double temp = b;
			  b = a+b;
			  a = temp;
		}
		 System.out.printf("%.2f",sum);
	}
}