题解 | #汽水瓶#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()) {
            int num = in.nextInt();
            if (num == 0)break;
            int extra = 0;
            int sum = 0;
            while(num >= 2) {
                if (num == 2) {
                    sum++;
                    break;
                }
                extra = num % 3;
                num = num/3;
                sum += num;
                num += extra;
            }
            System.out.println(sum);
        }
    }
}