JAVA实现”数兔子“（斐波那契）算法

import java.util.Scanner;

public class Rabbit {

public static void main(String[] args)
{
System.out.println("Please Enter the number of month:");
int sum;
Scanner s=new Scanner(System.in);
int month = s.nextInt();
Rabbit Rt=new Rabbit();
sum=2*Rt.count(month);
System.out.printf("The number of the rabbit is %d\n",sum);
}

public int count(int n)
{
int num=0;
if(n==1 || n==2)
num=1;
else
if(n==3)
num=2;
else
if(n>3)
num=count(n-1)+count(n-3);

return num;
}

}