Have a cow, it is born heifer beginning of each year. Each heifers from the fourth year, but also the beginning of a heifer born each year. Please programming in year n, when the total number of cows?

Topic: There is a cow, it is born heifer beginning of each year. Each heifers from the fourth year, but also the beginning of a heifer born each year. Please programming in year n, when the total number of cows?

Entry

A plurality of test input data examples, each test case per line, comprising an integer n (0 <n <55) , n the meanings as described in the title.
n = 0 indicates the end of input data, without processing.

Export

For each test case, the number of outputs of the n-th time in cows.
Each output per line.

Sample input

2
4
5
0

Sample Output

2 
. 4 
. 6 
Relationship between the number of cows and year in the following table

years	1	2	3	4	5	6	7
Quantity	1	2	3	4	6	9	13

 

 

In the fifth year since the second generation of a small cow began to produce so there are six cows, six years to the first year of production of small cow in a cow, the third year of two small cows produce two small cows so a total of 9 cows, so the table can be seen that the number of cows from the beginning of the first year started regularly, F (n) = F (n-1) + F (n-3), i.e., the number of cows is then the number of cows the previous year plus the number of cows the previous three years.

 

import java.util.Scanner;
public class Main {
public static void main(String[] args) {
　　Scanner in = new Scanner(System.in);
　　int n;
　　while((n=in.nextInt())!=0){
　　if(n>=1&&n<=4)
　　System.out.println(n);
　　else if(n>4){
　　System.out.println(Fun(n));
}
}
}
　　public static int Fun(int m){
　　　　if(m==1)
　　　　　　return 1;
　　　　else if(m==2)
　　　　　　return 2;
　　　　else if(m==3)
　　　　　　return 3;
　　　　else if(m==4)
　　　　　　return 4;
　　　　else
　　　　　　return Fun(m-1)+Fun(m-3);
}
}