View Code of Problem 48

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int n = scanner.nextInt();
		double sum = 0,a = 1,b = 2;
		for(int i = 0;i < n;i++) {
			sum += b / a;
			double temp = a + b;
			a = b;
			b = temp;
		}
		System.out.printf("%.6f",sum);
	}
}