每两个空瓶子可以换一个瓶子,有些取巧。

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            int emptyBottle = sc.nextInt();
            if (emptyBottle != 0) {
                System.out.println(emptyBottle / 2);
            }
        }
    }
}