View Code of Problem 71

import java.util.Scanner;
public class Main{
	public static void main(String args[]){
		int n,i;
		double sum=0;
		int a[] = new int[1000];
		int b[] = new int[1000];
		a[1]=2;a[2]=3;
		b[1]=1;b[2]=2;
 		Scanner cin = new Scanner(System.in);
		n=cin.nextInt();
		for(i=1;i<=n;i++){
			sum+=a[i]/1.0/b[i];
			a[i+2]=a[i]+a[i+1];
			b[i+2]=b[i]+b[i+1];
		}
		System.out.println(String.format("%.2f",sum));
	}
}