View Code of Problem 71

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int n=scanner.nextInt();
        int z=2;
        int m=1;
        double sum=z*1.0/m;
        for(int i=1;i<n;i++){
            int t=z;
            z+=m;
            m=t;
            sum+=z*1.0/m;
        }
        System.out.printf("%.2f\n",sum);
    }
}