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);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int num = in.nextInt();
            if (num == 0) {
                return;
            }
            int count = 0 ;
            //多出来的空瓶
            int newEmpty ;
            int remainingEmpty ;
            while (num > 1) {
                if(num == 2){
                    num++;
                }
                newEmpty = num / 3 ;
                count += newEmpty;
                remainingEmpty = num % 3;
                num = newEmpty + remainingEmpty;
            }
            System.out.println(count);
        }
    }
}