假設有50瓶飲料，

import java.util.Scanner;

/*假設有50瓶飲料，
 * 喝完3個空瓶可以換一瓶飲料，
 * 依次類推，請問總共喝了多少瓶飲料？
*/
public class Beverage {
	private int BeverageNum(int n){
		int num = 0;
		int surplus = n;
		while(surplus > 2){
			surplus -= 3;
			num += 3;
			surplus++;
		}
		num = num + surplus;
		return num;
	}
	
	public static void main(String[]args){
		System.out.println("您現在飲料的數量:N=");
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		Beverage b = new Beverage();
		int m = b.BeverageNum(n);
		System.out.println("您一共可以喝"+m+"瓶飲料!");
	}
}